There's a lot of misunderstanding about the value of critical strike around the healing community that I see. It isn't that critical strike deserves to be the stat that you stack or even prioritize, but it gets an unreasonably bad rap for all the wrong reasons...just like you or I did as a teenager. We can't do anything about our teenage years (unless you're still in them), but we can ease the social awkwardness of poor critical strike.
Too Random At Any Speed
This is, by far, the most common reason/argument that I see healers use in advising other healers to avoid critical strike. The syllogism goes:
Critical strike is RNG
RNG is bad
Therefore, critical strike is bad
For those unaware of the term "RNG," it stands for "random number generator" and it's used as a proxy for anything in the game system that has an element of chance to it.
Obviously, the conclusion in (3) is correct if we accept the premises of (1) and (2). So let's take a look at each of these premises and see if they hold up to focused scrutiny. I'm going to examine them in reverse order.
RNG is bad
A very common belief is that healers depend on reliability. DPS can exist in the chaotic maelstrom that is RNG, but no player tasked with keeping the raid alive can afford the luxury of rolling dice.
Is that true, though? I was talking about this with a friend of mine who tanks (Schriko of Ebon Plaguebringer) and he provided the perfect comparison point: tank avoidance stats. Tanks are no less tasked with keeping the raid alive (they are, in many ways, the choke point of the raid's jug of health...lose that stopper--the tank dies--and the rest of the raid's health is going to come pouring out soon after) and should presumably also be concerned with "reliability" over all else, if reliability was the be-all and end-all for those who's failures mean the raid dies.
However, no tanking guide suggests ignoring dodge and parry, the two "RNG" avoidance stats for tanks. Acquiring a fairly significant amount of each is an important thing for tanks to do (well, not parry so much for bear tanks, for obvious reasons!), even long before they can reach full combat table coverage.
The reason is that raid encounters are fairly long combat encounters. A tank will be exposed to a huge number of boss or add swings over the course of the encounter. The larger the sample size (that is, the number of opportunities to dodge or parry) the lower the volatility of the randomness. That is to say, if you have a 20% chance to dodge and only one chance to dodge, you're looking at an 80% chance to get exactly zero benefit from that dodge chance. However, if you have a million chances to dodge, you have so many chances to dodge that you'll almost certainly see right around 20% of those million chances dodged which means you reduced your damage over those million swings by a fifth, or 20% (assuming, for this very basic example, that all the swings were equal in damage done).
The same holds true for healers or DPS. The more spells you cast, the more chances for any type of RNG (critical strike, weapon or trinket procs, etc) to stabilize around its numerical value and play out like a static value (as the 20% dodge plays out like a 20% damage decrease over a long combat).
Critical strike is RNG
At its base, critical strike is clearly RNG...the value denotes the chance for a heal (or damage, but I'm mostly focusing on healers here) of double the value.
That said, there are some things that you should keep in mind when considering critical strike as a healer.
The first thing is that some healing class-specs have a much, much greater number of opportunities to generate critical strikes. For example, let's look at holy priests. The majority of their healing comes from Prayer of Healing, Circle of Healing and (if the raid can spend a fairly large amount of time stacked up) Holy Word: Sanctuary.
Prayer of Healing can hit five players at a time. Circle of Healing can hit six, glyphed. Holy Word: Sanctuary can hit as many people as stand in it, so up to twenty five people in a raid setting.
That means that on each Prayer of Healing cast, you have five chances to critically heal, six chances with Circle of Healing and an indeterminate but high number of chances with Holy Word: Sanctuary (assuming you're making smart decisions about when to use it).
This stands starkly in contrast to a healer (or DPS) who casts lots of single-target spells. Those players can still generally count on critical strike largely smoothing out over an entire combat, but are more volatile from cast to cast. A holy priest really isn't, because their model is to cast, in essence, a ton of small heals...which greatly expands their sample size even on a per-cast basis. For a holy priest, it's not all-or-nothing even on a per-cast basis.
Returning to the tank avoidance stat analogy for a moment, if there were a type of tank that had the ability to break each boss swing into seven smaller pieces of damage, each of which could be independently dodged or parried, then dodge or parry would be even less volatile for the tank. That's the tanking equivalent of healers who cast a lot of area of effect (AoE) heals (even if such a tank doesn't currently exist...but maybe it should!).
This, of course, is not limited to holy priests. Restoration druids also have a lower volatility per cast, due in part to their AoE heal (Wild Growth) but also due to the fact that the ticks of nearly all heals-over-time (HoTs) can critically strike. HoTs, like AoE heals, also subscribe to the model of smaller but more numerous heals, which substantially reduces the volatility per cast.
Restoration shamans, with Chain Heal and Healing Rain, fall into this boat if they're primarily raid healing. Holy paladins have been pushed into this boat by the redesign of Holy Radiance (and its resultant synergy with Light of Dawn).
To be perfectly honest, discipline priests can end up here, too, if they find themselves spamming Prayer of Healing as raid healers, which is a fairly common style for discipline priests.
Critical Conclusion
Let me clarify what I'm saying here. I am not remotely saying that critical strike is the best stat for each of these class-specs. What I am saying is that critical strike is not a poor choice due to its "unreliable RNG aspect." Critical strike tends to stabilize over raid encounters that aren't extremely short and spec or playstyle can even stabilize critical strike on a per-cast basis.
Looking at critical strike as an unreliable stat that makes healing raid encounters as chancy as rolling dice is simply the wrong way to approach analyzing our secondary stats and gearing.
There are, certainly, other factors to consider* in critical strike but unreliability is really not one of them.
The idea of this post is not to make a full review of critical strike as a stat, but rather to strenuously object to one of the most common philosophical arguments put forth within the healing community about critical strike.
*Factors To Consider Not Expanded On In This Post
The cost, in rating, to get a percentage of the various secondary stat
The talents that are affected by critical strike
The spells you use that are affected by critical strike
The effect on mana that the various secondary stats exert
The value other secondary stats have to your spell usage (opportunity cost of critical strike)
"Shield spam" has become a term of ill-repute in the discipline priest community. It's spoken of either in whispers about the "bad old days" or else in the sharp, mocking tones of what not to do. Only the most degenerate discipline priests would encourage shield spam. It speaks to loose healing morals and, yes, even a bit of healing perversion. Shields are to be enjoyed in small quantities, not to gluttonous excess.
That is why I'm here to tell you to reject those stereotypes. Even good-hearted people can blast out bubbles. It's not the evil that you've all heard it is. It can--nay, should--be done. Don't listen to your neighborhood priest telling you that it's sinful.
That said, we should probably define what we mean by "shield spam" because multiple behaviors have been lumped into that one term and they are not all the same.
Let's start by examining where the term really sprang into prominence and trace our story from there. This, it turns out, may run a bit long but I promise there's a point at the end. And a pizza party. Pertinent point and pizza. And cold beer.
Come with me, then, back to those heady days of Wrath...
Spammy Shield Spam
Welcome to Dalaran! Do you have any emblems of frost to turn in? And how about those vrykul, eh?
I hope I've adequately set the mood. Back in this era of World of Warcraft, discipline priests were slowly but surely rising in the world of healing. In prior eras, discipline was really more of the PvP spec and holy was the healing spec for priests. However, the tree was revamped in Wrath and PvE discipline priests were becoming more and more populous.
Oh, sure, there was still residual persecution that they faced. They were regarded with suspicion, not being holy. Absorbs were a bit of a new mechanic to much of the playerbase and no one really paid attention to absorb values, which made discipline priests appear to be rather ineffectual, what with Power Word: Shield and Divine Aegis being completely ignored by almost all healing meters.
However, as raiders were graduating from Trial of the Crusader to the final raiding tier of the expansion, Icecrown Citadel, people were understanding the power of the absorb. High-level players had understood it long before, but it gained popular acceptance. Now, discipline priests were not just being accepted but often actively recruited as they carved out their own niche. Discipline priests weren't healers, they were shielders! You could almost think of them as a huge damage debuff on each and every boss.
This was a double-edged sword. It made discipline priests a rather necessary part of any raiding team capable of picking and choosing their raid compositions, as much so as getting a shaman in for Bloodlust or having a druid who could Rebirth. Having such a valuable niche in raid teams is obviously a nice thing...damned are the poor souls who play class-specs marginalized by current raid design.
On the other hand, it was a terribly boring playstyle, especially in 25 man raids. In 25 man raids, very literally a discipline priest's job during an encounter was to do nothing but blanket the raid in shields. And then do it again. And again. Until the boss was dead. Other healers were there to do the actual healing, after all. In 10 man raids, it was a little better, purely because there weren't enough people to shield before the Weakened Soul debuff prevented you from casting more shields. At that point, it was reasonable to cast an actual healing spell.
So discipline priests were in a bit of a bind...the niche that gave them ready access to raid spots also trapped them into a rather unenjoyable style of playing. (This wasn't purely confined to discipline priests, as I know there are restoration druids out there who have nightmare stories of being Rejuvenation bots. But I think it was most pronounced for discipline priests.)
Our Story Runs Into A Twist
Blizzard agreed that it was a trap. Their design philosophy had been slowly attempting to weed out repetitive, or One-Button, play. Discipline priests sometimes using nothing but one spell in raids didn't escape their notice. So they changed it. So mighty was their change to the discipline priest spec that they named an entire expansion for it: The Cataclysm.
Perhaps you heard about it? The change resulted in many fires around the world.
What they did was make Power Word: Shield really weak. It was brilliant. Why would you spam a spell that wasn't very strong? You wouldn't. That Blizzard, always thinking.
Well, as it happened, trying to reduce a spec's dependence upon their best and most iconic spell by making it terrible didn't do wonders for balance, that nasty issue that boils down to "Do you get to raid or not?" Discipline priests were pariahs again. Go holy or go home. The chants were hurtful.
So Blizzard did what any wise design team would do. Turn the dial the other direction as far as it would go. Suddenly, Power Word: Shield was really strong. Discipline priests were great again...in fact, they were recording by far the best parses overnight. No other class could compete.
"Hmm," said Blizzard. "That was unexpected." Also, there was this issue of discipline priests spamming their newly god-mode spell on everyone again. Also unexpected.
So now Blizzard needed a solution that did not involve turning that dial at all. Turning the dial on Power Word: Shield, you see, revealed a problem inherent in WoW balance. A spell you can use whenever you want will either be strong enough that you will use it first, last and always or else so weak that you will never use it. For if it is the strongest spell right now, it will probably be your strongest spell a moment from now. And if it is not your strongest spell right now, it probably won't be your strongest spell a moment from now.
The answer resided in the other dial that Blizzard had ignored in Wrath (which caused that previous logic about "strongest spell now->strongest spell always" to be binding in nearly every case) but used with abandon in Cataclysm...the mana cost dial. True to the Cataclysm healing model, which held that you don't simply min/max based on power of spell but min/max such that you don't go out of mana in the first minute, they increased the mana cost of Power Word: Shield greatly.
That changed the game significantly for discipline priests. The shield was still really strong, and it gave mana back every 12 seconds, so it was still useable...but "shield spam was dead for good" (I place that in quotation marks because it was probably the most common quote of the past year, it even featured on the cover of a Time magazine).
This was driven home with a peculiar sternness on forums and guides for discipline priests. Perhaps the people saying it felt it was necessary to say it with passion to break the dirty habits people had built up, but a great deal of scorn and derision was heaped upon the concept of shield spam (in my experience, at least). Not that it really required stern insistence...any discipline priest that tried to spam shields during a raid encounter, Wrath-style, would find themselves as merely a decorative prop pretty quickly, completely out of mana (OOM) and therefore unable to help much. This was a lesson as subtle as a jackhammer to the head.
And lo...it is still impossible. Unlike the latter stages of Wrath, where no spell could really run you out of mana, casting shields non-stop on a raid group, even in 10 man, will solidly OOM you.
So What's All This Talk Of Shield Spam, Then?
The problem is, "shield spam," which was originally applied to casting shields on each raid member robotically, over and over, is now being applied to any behavior involving using lots of shields.
The fact of the matter is that absorption is still the healing space of discipline priests. That is where you can add the most value while still allowing all other healers to do what they do best. While holy paladins have entered the space to some extent (to say nothing of the abominations known as blood death knights), it's still an important niche that discipline priests largely dominate. Damage prevented or mitigated is more valuable than damage taken and then healed up (the easiest way to see this is to compare the value of absorbing a 30k hit to a player with 24k health remaining, versus attempting to heal it up after).
While Divine Aegis does yeoman's work in terms of absorption, there's no faster way to get on-demand absorption out on the raid than what you might call "spamming" shields.
The key here, of course, is that you must choose when it makes sense to spam those shields. Your mana won't support doing it all the time. And the mechanics of bosses (along with a duration lowering change that I neglected to mention earlier) are such that ill-timed shield spam will come at great mana cost for no benefit as the shields mostly drop off due to expired duration without absorbing any damage at all.
So you absolutely have to pick your spots intelligently. However, if you do, there's a world of benefit to be mined from strategic shield spamming. Getting ten shields out ahead of a big raid-wide damage spike can effectively increase your raid team's "clutch heals per second (HPS)" by which I mean that if you're using GCDs during a low-stress period to put up shields that will be eaten by a high-stress period, it frees you up to cast other spells during that high-stress period. You're borrowing time from a low-stress period to lessen the difficulty of a high-stress period, in a way other healers largely can't. Absorption shields are about the only "preventative healing" (though HoTs can be used in a somewhat similar way, though less efficiently for the same purpose).
You won't be able to shield to the exclusion of all else, even if you pick your spots. There are times, especially in 10 man raiding environments, where helping your fellow healers move life bars will be necessary. However, the more you bias your casting patterns in favor of Power Word: Shield, the more you can help your raid team even out the spikiness of the overall incoming damage of the encounter. It also has the benefit of clarifying your stat choices for gemming, enchanting and reforging. If you know you will be using as much of your mana as possible (over the entire encounter) on Power Word: Shield, then you know mastery is your best bet.
This is Smart Shield Spam(tm). This is good. This is a perfectly responsible way to play discipline priest. There are other perfectly responsible ways to play a discipline priest, but don't let others lazily say "Shield spam is bad, mmmkay?" Make sure they define what they mean by shield spam...if they're talking about Wrath-style bubble botting, nod at the obviousness of their observation. Yes, you can't do something that you don't have the mana for. However, if they're advocating shielding as little as possible (some even claim you should largely only be shielding the tanks or only shielding to proc Rapture) then reject that supposed truism. Intelligently spamming shields at the right times can be an extremely powerful way to play (I would argue the most powerful way to play)...you should experiment and see how far you can stretch Power Word: Shield, especially as you push into progression fights that stretch you to your very limits.
In case you don't get the (old) meme reference of my post title:
Okay, now that that's out of the way, let's talk about "healing space." This is not an alternate zone that healers live in, perhaps like the Emerald Dream area in the Valthiria Dreamwalker encounter. This maps out where each healer excels, when able to do what their class abilities optimally allow for, to create maximum synergy between the healers in your team.
This is much more crucial in twenty five man encounters, when you have more healers and significantly more overlap. It does happen more often in ten man encounters that healers get isolated more on their own healing islands, in which case you cannot "specialize" as much. However, as you push into heroic modes, even ten man raids are well-advised to try to organize the encounters such that all the healers you're using can cover all the same targets (everyone). This is not always possible but, when it is, that's where heal space analysis is valuable.
The long and the short of it is that if two or three healers can cover the same targets, you maximize their effectiveness by A. making sure the two or more healers have complimentary powers and B. having each healer bias their spell usage toward specialization.
So what heal space does each class inhabit? Let's take a look.
Note: The next four sections are a quick look at what constitutes the core of each healing class (and spec, in the case of priests). If you would find a run-down of these class-specs dull, skip past the sections with class headings. None of those sections contain theory, just my views on what (essentially) makes each class-spec unique. That "healing world view" is important to the theory that comes later, of course, but I don't believe my healing world view is controversial.
Druid
For the last (large number here) tiers, druids have been the reigning overall healing throughput champions. With their "creeping heals" (my term for healing that's always creeping upwards, everywhere, all the time), they're almost like the inverse of a damage aura...they provide a healing aura (as it feels from the outside, this is in no way to suggest that it's passive on their end) as everyone's life bars are always moving upwards thanks to them. They can Rejuvenation blanket when everyone's taking AoE damage, Wild Growth on cooldown, Swiftmend to create a healing circle under a group of people and keep potent HoTs (the aforemention Rejuvenation and Lifebloom) rolling on the tank(s).
And then, of course, there's always the raid healing bomb of Tranquility lurking.
The reason druids have been such potent raid healers is because they're not provided any absorption or mitigation abilities (leaving aside the personal cooldown, Barkskin, which is of only niche value to a restoration druid). Their contribution is entirely wrapped up in moving life bars, so they move them a lot.
While they can use direct heals to keep someone, like a tank, alive through continuous damage, it's not where they excel and it's not the optimal use of their mana. "Optimal" is the crucial word for this analysis, since we're trying to maximize a healing team.
Paladin
For the last four or so tiers, at least, paladins have been somewhere between very strong and broken-strong (ICC days) as tank healers. They've been given some new tools in Cataclysm (notably, Holy Radiance and Light of Dawn), but neither has changed the fact that the bulk of their work is done with strong single-target throughput. Their healing space will probably have to be re-evaluated once patch 4.3 arrives, due to the major changes to how Holy Radiance will work.
Holy Radiance (thus far) has been constrained by a cooldown, making it unspammable, and Light of Dawn is a holy power release, so it's also unspammable, since they need to build up holy power in between usages.
That leaves paladins the most beholden to the "Three True Heals" model that Blizzard has tried to build into every healing class (with varying levels of reliance across classes). Since their "quick, mid-level heal" Flash of Light is not generally considered a good use of mana, they end up heavily reliant on four spells with a heavy emphasis on the first two (being the ones without a cooldown or holy power requirement): Holy Light, Divine Light, Holy Shock and Word of Glory.
So direct heals are what paladins will be dealing in, largely.
Shaman
Shamans have an interesting concept. The majority of their healing is direct, though they also use an area HoT (Healing Rain) and a more traditional HoT that procs from one of their main direct heals (Riptide).
What makes shamans interesting is their mastery, Deep Healing. The upshot of their mastery is that the lower health their healing targets, the more powerful their healing spells are.
So shamans are a mixture between direct healing and healing over time, with potency inversely related to the health of their target.
Priest
Priests come in two flavors, of course. There is the Discipline flavor and the non-Discipline flavor (I kid, I know that one of the healing trees is named Holy, even if Blizzard doesn't).
Discipline priests have always had a unique mechanic (which holy paladins have recently infringed upon with their mastery, but not very successfully except in niche cases) known as absorption. These are shields that absorb some of the incoming damage before it can affect the player. Shields are the centerpiece of the discipline spec. And while discipline priests (like all healers) have an assortment of direct heals, the other thing they have which is more or less unique to them is mitigation. This is similar to absorption, in that it prevents damage rather than healing it, but rather than absorbing it, it reduces the degree of the damage by a percentage basis. So instead of absorbing 45,000 damage, it will reduce the incoming damage by 10%. One of their signature mitigation spells is a tank cooldown, Pain Suppression.
Holy priests on the other hand do very little absorbing and mitigation. They are more similar to druids in that they use healing over time and direct heals to do lots of healing over the encounter time. While druids bias more toward HoTs, holy priests bias more toward direct heals. Unlike druids, holy priests do have a potent tank cooldown, Guardian Spirit. As you might notice, Guardian Spirit is kind of the reverse doppelgänger of Pain Suppression. While Pain Suppression mitigates damage by 40% on a target, Guardian Spirit allows for 40% more healing on the target. Guardian Spirit has the added benefit of preventing a death, which does make it a bit more powerful but also compensates for prevented damage being less risky than healing damage after the fact, a factor that makes damage mitigation more powerful than a healing boost.
Healing, Economics...Same Thing
If all of that was a fairly old hat recap of the healing class-specs, I apologize. In terms of structure, I felt it was important that we establish what each healer is doing at his/her core before we start parceling out territory in the healing universe.
The central concept of healing space is this: While every healer can do a variety of things and fill any role, especially direct healing of all the things, the highest efficiency is achieved by each healer focusing on the things they do best and avoiding the things they don't do as well as another, even if they can do it well. If you've studied economics, this should be a pretty familiar idea, because it's mirrored perfectly by the idea of Comparative Advantage. By specializing in what you do best (rather than doing everything you do decently), you increase the efficiency of your team. To make the parallel to the economic theory, if you analogize your healing team to a world economy, your healers are trading products (throughput) for currency (mana efficiency) with each other.
The economic theory of comparative advantage is wonderfully counter-intuitive to most people when they first encounter it. It generally isn't an immediately obvious idea that, even if you're good at a number of things, if you exist in a world with potential partners who do anything better or worse than you you're better off specializing rather than doing everything you're good at.
Blizzard made sure every healing class can fulfill any role competently with the advent of Cataclysm, because they didn't want raids to feel locked into specific class make-ups rather than just bringing the people who were either best or else they most enjoyed playing with. So the changes they made to achieve this made every class a jack-of-all-trades to a certain extent. However, they didn't give every class and spec every ability or equalize their power in every role. They just ensured that every class and spec reached at least a minimum baseline in every healing role. This leaves enough difference between the class-specs to leverage for the sake of efficiency (and when I say "efficiency," I mean optimizing throughput for a healing team).
So how do we leverage this? To put it very simply, we identify where each class-spec's best use of mana lies and create a healing scheme whereby each healer is biasing their spell choice heavily in favor of that best use of mana. That is optimizing healing space.
This may sound like what healers should always be doing, but it's only possible in group play in which there is more than one healer. In a five-man environment, for example, where there is only one healer, you cannot specialize. You must cast all the spells necessary to keep everyone alive. This means some amount of direct healing as a druid, for example, even if direct healing is not your forté, because HoTs alone aren't going to keep a tank up through heavy damage. The economic theory of comparative advantage is useless if you are alone on a desert island, and optimizing healing space is worthless when you are a healing island in a five-man group.
No, it gets interesting when you are in a ten man or, especially, a twenty five man raid. The larger the group, the more healers. The more healers, the more specialization each healer can engage in, because a lot of niches can add up to a coherent whole. A single niche is just a niche.
Establishing The Foundation Of Healing Space
I primarily raid in ten man groups, so I'll primarily use that as the example. However, I'll note how this really flourishes in twenty five man groups at the end.
My raid group generally employs a healing team of a restoration druid, a holy paladin and a discipline priest (hey, that's me!). This has actually often been called the "holy trinity" of ten man raid healing teams and for good reason as we'll see from a healing space analysis. How do we leverage these three classes optimally?
The simplest approach for a healing team is what I like to call "see damage, heal damage." If someone is below full health, cast the appropriate spell (factoring in time urgency, amount of healing needed and mana efficiency required). This isn't particularly organized but it can actually work, especially if the healing team is extremely familiar with one another. The primary drawback here is that the disorganization can lead to sub-optimal healing: multiple healers addressing the same damage (leading either to overhealing or else a healer canceling their spell mid-cast, wasting some amount of time) and certain targets not receiving heals quickly enough.
One step up is straight healing assignments. Healer A will heal the main tank. Healer B will heal the off-tank. Healer C will heal all the non-tanks. This is much more structured. Overhealing will be reduced because, at least notionally, healers are not cross-healing the same targets. Every target has their dedicated healer and thus knows exactly what healing that target is receiving because it all comes from himself/herself. The primary drawback here is that overly strict adherence to assignments can leave healing potential on the table (Healer A being idle when the main tank is at full health while Healer C struggles with a burst of raid damage) and deviance from assignments leads to a greater and greater descent into the previous "see damage, heal damage" paradigm, with its own attendant drawbacks.
While the second option (assignments) is generally better regarded, each paradigm actually has its strengths. "See damage, heal damage" ensures that all the healers are capable of remaining active at all times (at least, all times in which there is damage to heal) which prevents useable healer casting time and mana regeneration from being wasted (a healer sitting at full mana is wasting all their itemization and talents that provide mana regeneration), while assignments provide the structure to keep healing from being wasted.
The ideal situation would be to marry the strengths of each paradigm into one, without also importing the attendant weaknesses. A healing space paradigm does just that. Let's look at how this works.
Crafting Healing Space
A restoration druid, as we noted, is best at keeping continuous healing "growing" on lots of targets at once, whether that's through Rejuvenation on multiple targets, Wild Growth or Efflorescence parked below a stack of raiders.
A discipline priest excels at preventing incoming damage.
A holy paladin is most powerful at pumping out strong direct heals on single targets (the value of which is amplified by their "reflection" mechanics, Beacon of Light and Protector of the Innocent...much as a battery of mirrors serve to focus and intensify a laser beam).
So we craft a healing space in which:
The druid does keep her HoTs "growing" on as many targets as she can sustain and/or makes sense for the encounter but does not cast many single target heals.
The holy paladin does cast her powerful single target spells on targets who are either particularly under siege or else are particularly low but does not concern herself with damage prevention (gears away from mastery) or heals over time (Holy Radiance, which has a mana opportunity cost).
The discipline priest does cast her shields and mitigation spells often to slow the damage on targets likely to take damage in the near future, but does not spend much time or mana casting HoTs or direct healing spells.
A crucial point here is that there are no explicit target assignments. You are not assigning the holy paladin to one or both tanks and the discipline priest to one or both tanks. You are not assigning the restoration druid or the discipline priest to raid healing. Instead, if you'd like to think in terms of assignments, you are assigning each healer to a specialization.
A discipline priest is optimally using his mana when he casts a shield likely to be consumed by incoming damage. A restoration druid is optimally using his mana when he casts HoTs (whether single target or multi-target) that are likely not to go as overhealing. A holy paladin is optimally using his mana when he casts a powerful direct healing spell on a target at a low enough health that little of the direct heal goes as overhealing, and the target of the heal reflection also is low enough health that little of the reflected heal goes as overhealing.
The result is that, as long as there is damage to be healed, you have healers who can be active and engaged, yet there is implicit structure that minimizes the overhealing that chaos can cause. The druid is a champion of overall healing, but all that creeping healing is useless if targets die before they can tick back up to a safe level. That's where holy paladin direct heals come in, swiftly (relative to druid HoTs) pushing a dangerously low target back to a safer level where the slow healing over time can finish the job passively. But the paladin's big heal is useless if the target dies before the heal lands (or before the paladin can find time to cast on that particular target). That's where discipline shields come in, providing an instant buffer on targets in critical condition, keeping them afloat until the healing of the paladin and druid can save them.
At a more abstract level, the discipline priest provides a preventative umbrella over everyone, underneath which the druid's garden of HoTs provide a "healing aura" constantly moving everyone upward and the holy paladin combats spikes downward in health to anyone with spikes upward in health through spells.
In Conclusion, More Explanation
In this healing space, each healer has a clear-cut role, which allows them to fluidly move between the same targets, but in their own space. Think of it as a separate dimension...each healer is their own island, in their own dimension. You, as a healer, are responsible for everyone...but only within that dimension. As long as every healer optimizes the throughput of the spells that make up their dimension, the healing team is optimizing their overall throughput.
Except when necessary, you need to resist moving into a fellow healer's dimension. Each time you do so, you detract from the efficiency gains. Your healing team has only so many GCD's (global cooldowns) and mana to work with over a given encounter length. Using your GCD and mana to address a small bit of damage on a target, when a druid's HoTs can address it, may seem harmless enough, but it's a GCD and mana you could have used casting a Power Word: Shield. On a one-off basis, it doesn't matter much...but these little decisions add up over the course of the encounter and undermine the benefits of specializing within the crafted healing space.
For the sake of brevity (this post is barely more than a haiku in length and I like that succinctness), I won't go through a similar healing space crafting for every combination of healing classes. But you can see the format: identify what a healer does that is an optimal throughput use of their time and mana and give them that specialization across the entire raid and task them to use non-optimal spells as little as possible. A shaman, while not included in my example healing space, can easily be crafted a space based on their unique power on low health targets. All that's necessary to create these types of healing spaces is multiple healers. There can even be duplicate class-specs as long as each of the duplicates can, through talents, gearing or playstyle, provide a different specialization (two holy priests can each specialize differently based on different chakra states, two discipline priests can provide absorption and direct heals, etc).
The key is for each healer to decide, for an encounter, what they will be spending their mana on, working to make that efficient (through itemization and talents) and then sticking to it as much as possible. If you've geared and talented for making your direct heals as powerful as possible and then bias your spell choice heavily to direct heals, you can achieve a lot more than spreading your gearing and talents out and trying to do lots of different things...as long as other healers are picking up the other forms of healing.
As I mentioned previously, this can be taken to an even greater extent in twenty five man raids, where instead of two or three healers, you're working with five or six healers. Since every healer is still responsible for everyone, you handle more healers by breaking healing space into even more granular roles. How about a holy paladin who specializes in stacking mastery for absorption and focuses on overhealing targets to build up larger and larger bubbles on targets she expects to take big damage soon? That's happened in some world-ranked raid groups. How about a discipline priest who stacks crit and haste in order to pump out Prayers of Healing to coat the raid in Divine Aegis bubbles (since Power Word: Shields can't have constant uptime due to Weakened Soul)? These are the types of niche roles that ten man raid healers simply can't afford to try because it's too small a niche for the roughly 33-50% of the total healing you're responsible for. The more healers, the more specialized you can afford to be and the more specialized your healers must be to fully leverage each healer.
I'm Done, Thanks For Reading
We are here to protect you from the terrible secret of (healing) space.
Actually, mastery should be in there too, of course, but the title seemed punchier with just two parties. This post is really concerned with haste versus crit and mastery, though.
As any healer who wastes spends time reading about World of Warcraft knows, haste achieves its throughput at the cost of mana longevity*. In order to realize the gain of haste, you need to push more spells out in the same space of time...which means more mana burned through more quickly.
*Disclaimer coming in the next section, druids.
However, haste provides a consistent, predictable gain to every spell (unlike critical strike). And, unlike mastery, the gains are unambiguous: when you measure heals per second (HPS), every second you remove from the denominator is going to increase the HPS ratio. It is throughput in its purest form.
This has led many people to make statements along the lines of: "If raw throughput is what you're looking for, haste is ideal. If mana efficiency/longevity is still something you need, then it becomes trickier." Explicit in this is the belief that haste is the clear winner for throughput and implicit is that critical strike/mastery are better for mana longevity.
I certainly am not going to debate the second part. Haste is clearly not the best stat to stack from a mana longevity perspective. It is the healer equivalent of the proverbial "burning the candle from both ends." You're going to get a burst of production, but at the cost of sustainability.
But Is Haste Really King For Throughput?
Let me make this disclaimer right off the bat: This entry regards non-HoT healing classes. Haste has a pretty significant effect on HoTs and without any adverse effect on mana longevity. HoT classes need to be dealt with as a separate category when it comes to haste, so none of this is meant to address druids, holy priests or even holy paladins (while perhaps not thought of as a HoT healer, their heavy reliance on Holy Radiance tends to throw them into this category).
That leaves discipline priests, primarily, and potentially restoration shamans (this article can apply to a shaman who largely tank heals and doesn't make heavy use of Healing Rain).
So for these healers, for whom haste is primarily a means to reduce cast times (though lowering the global cooldown is also potentially useful), how should we value haste even if we do not consider the longevity aspect?
Simulations and spreadsheets will generally show haste providing the biggest throughput gain (unless you are a disco priest that primarily spams shields). However, there is one major problem with this, which is not generally priced into tables of throughput per stat, though can be verified with certain simulations.
Any interruption in casting instantly devalues haste-boosted throughput. A lot. This includes purposeful, chosen interruption (a period with little to heal or a desire to regenerate some mana) and forced interruption (due to mechanics or movement). This also means that if you run out of mana mid-combat (or slow your casting due to the danger of doing so), the benefit of all your haste plunges nearly to zero.
The reason for this is obvious: Haste is all about pushing more spells into a space of time. For an encounter, this means pushing more spells into the entire encounter than you could have otherwise. To do this--to push more spells into the entire encounter using haste--you'd need to be chain-casting from start to finish. If you do not currently do that, you can already "haste yourself" by filling those periods of inactivity. If mana issues prevent you from doing so, haste will not help you. Haste will only ensure you cast the spells you already do a bit faster, actually lengthening your periods of inactivity.
Even if mana issues don't prevent you from chain-casting, if you ever stop casting to move, there's a good chance you're losing most or all of your haste gains. The amounts of time you're acquiring from haste, at these gear levels, are objectively quite small, measured in seconds over an encounter length. Those numerically small gains are significant from a throughput perspective (after all, healing power is all measured in small percentage gains)...if you're not losing those seconds here and there by not casting.
Most people aren't chain casting powerful spells from pull to kill (if you're using weaker spells in order to keep activity up, you're simply trading one form of throughput loss--inactivity--for another--low throughput spells). Even if they have strong mana regeneration and are good about finding things to do on the move, it's the very rare healer that keeps pushing out large heals with no interruption at all. If you can do that, then haste will perform pretty similarly to the simmed value and should, indeed, be tops (assuming you're not a shield spammer!).
However, for most people, haste is simply not as strong a stat as is often claimed. That is not to say it's a poor stat or useless. Far from it: there are those who actually don't care about encounter-long output and are there to provide bursts of healing over small periods of time, so inactivity later is not a concern. However, even for those people, it bears noting that haste actually has a "ramp up time" for value. It takes a reasonably significant amount of time (as compared to the encounter length) to realize the benefit of haste; that is, to have saved enough time to be able to push out one extra spell due to haste. This amount of time is on the order of a minute or more, so if you're attempting to use haste to power "bursts" over shorter periods of time than a minute, you may not find that the gains are worth the opportunity cost (of the secondary stats you could have had in place of the haste you stacked).
The Final Act
At the end of Wrath of the Lich King, it made sense to have a ton of haste. Mana pools were large, unspoiled and filled with plentiful and delicious fish. You could stand on one end of a healer's mana pool, look out over it and not see the other side even on a clear day. It felt like mana was infinite.
A maxim took hold then, known as "ABC," or "always be casting." The first step was to, as I put it above, haste yourself by filling every period of inactivity. Even if there was nothing to heal, start a cast on someone (like the tank) just in case damage happened before your cast completed. If you were a discipline priest, you were encouraged to fill any free moment putting a shield on someone. Do something--anything. Inactivity was the mind-killer.
In such an environment, haste makes plenty of sense. If you're straining to find ways to use your mana to increase your throughput, having lots of haste allows you to spend even more mana (that your cup runneth over with) to squeeze more spells into the encounter.
That is not the situation healers found themselves in, in tier 11 raids and, largely, it still isn't the situation for most healers today in tier 12 raids (as partially evidenced by the outcry from many priests about the lack of spirit cloth drops from Firelands bosses). If you do feel you're in that position, knock yourself out with haste and be sure to always be casting. However, for most healers, that situation may only arrive in the final half year or year of this expansion.
Until then, you'll want enough haste to feel "comfortable" that you're not going to lose your tank during a Greater Heal or Greater Healing Wave cast, but you don't want to overdo it. It's not head-and-shoulders better for throughput and has an adverse effect on sustainability over an encounter. Look into adding critical strike and mastery to your portfolio. As in the stock market, diversification is your friend.
In the first tier of raiding in Catalcysm, tier 11, I almost never used Heal. It was just too slow and weak. It was like a caster DPS blasting away with her wand. It will have some effect, but not enough to matter.
However, I'm noticing something interesting at the start of this new raiding tier: Heal isn't half bad. It's still much, much weaker than Greater Heal, Flash Heal and Penance...but it's actually useful now for a few reasons.
Heal Has Been Powered Up By Gear
One is that with gearing getting better, the speed of the heal is no longer crippling and the size of the heal now has the potential to move raid member's health bars (even if not by a huge amount).
"Sure," I hear you saying. "Heal is better with better gear. Big deal. Every heal is better with better gear, and everyone's health is increasing too. Holy Nova is better now, too. Time to use Holy Nova?"
No, of course not. Don't be silly. There's never a time to use Holy Nova unless it's to run around the Molten Front dailies, spamming it so that you get kill credit on everything.
However, throughput gains from intellect, haste, crit and mastery seem to be scaling with gear more than health pools (and, therefore, boss damage since boss damage output has to be firmly correlated with health pools*).
*Theoretically, boss damage output could be untethered from health pool size...but the only way for that to be viable would be if healing spell output were utterly massive, which would still mean Heal's output would outstrip health pool scaling and move life bars nicely.
Therefore, Heal is actually more powerful relative to this tier than it was relative to the last one. Sure, Flash Heal, Greater Heal and Penance will always do much more, but Heal is cheaper. Which means...
Healer Auto-Attacking (Or Wanding) Has Value
Any time damage is pouring in in a big way, you'll have other priorities, like the aforementioned bigger spells as well as Binding Heal and Prayer of Healing. But at the start of this tier, mana efficiency is going to matter again. Perhaps not quite so much as at the start of the last tier (since base mana didn't go up, so spell costs remained the same while mana pools are increasing) but with incoming damage higher, your larger mana pools will be challenged again.
And if you're a healing priest, Blizzard has a special gift for you: exactly zero of the cloth drops in the Firelands have spirit. That's not to say spirit doesn't exist for us; you can get spirit on valor point gear and there is spirit on some of the trinkets and jewelry (that every other healer will be after too)...but at least for a while, you may be packing fewer spirit pieces than you'd prefer.
Therefore, you want a tool that can have an effect without affecting your mana much. Enter Heal. The spell is at the very least mana neutral and may even be mana positive depending on your spirit levels and any mana regeneration tools occurring at the time (for example, Replenishment). By "mana neutral," I mean that you regain Heal's mana cost during the cast time and by "mana positive," I mean that you regain more than Heal's mana cost during the cast time.
This means you can still make a contribution essentially without expending mana or while (more slowly) regaining mana. This is useful during periods of low damage, to marshal your resources for the more intensive periods, and for when you run yourself right out of mana. Sure, being limited to Heal makes you a minor contributor at that point, but at least you're still in the fight rather than an interested onlooker.
Let's also remember that Blizzard's little surprise for healing priests (no cloth spirit drops) has a benefit: It means more pure throughput stats, since that stat budget has to be filled up one way or another. Now, until spell costs become completely trivialized, I'm a big believer that spirit is the best secondary stat because it can either give you mana regeneration when you need it, or can be converted into throughput when you don't. That said, spirit is definitely not better for pure throughput than mastery, haste or critical strike. Having more of those stats will make your Heal spell (in addition to all your others, of course) even stronger, allowing you in a strange sense to convert throughput stats into mana efficiency: You can cast more Heal and therefore conserve mana.
Critical Strike: Now With More Critical Goodness
As I'm sure you're aware, the latest patch brought with it a boost to all healers: critical heals now provide double the original output instead of one-and-a-half-times the original output. That means that when you drop in a critical strike Heal, you'll see a surprisingly large number. I've had Heal hit for 20k+ in heal-y deliciousness. That's pretty not bad for essentially no impact on my mana bar.
You can't count on a critical strike, but you can cast Heal on a target, hoping for a critical strike or two, until the target (or another target) is beginning to look a little green around the gills, in which case you can switch to bigger heals. A run of two or three critical strikes can result in fairly legitimate healing, leaving you awash in mana (which is blue and cooling to the mind and skin).
Tier 11 Two-Piece Bonus: How Ya Like Me Now?
It's still not exciting. That said, it's actually relevant now. I completely ignored the set bonus during the previous tier because I never cast Heal during raids, unless it was while fighting trash and everything was under control with little healing to be done. So the set bonus had no benefit at all for me.
Now, however, until you replace at least three pieces of your tier gear, this bonus will help. As we just noted, critical strike Heals can make a real difference and a 5% higher chance of getting them is a non-trivial effect. It seems like a small difference, our effectiveness is measured in a percentage here and a percentage there. It's a small chance for chaining a couple or three critical strike Heals together and those add up.
Bringing It All Home
Don't forget that Heal (like Flash Heal and Greater Heal) will reduce the duration of Weakened Soul, allowing you to get a Power Word: Shield back up on that target sooner. Similarly, Heal (like Flash Heal, Greater Heal and Binding Heal) has a chance to proc a free and instant Flash Heal if you have the Surge of Light talent. In both cases, Heal is a cheap way to take advantage of those talents, allowing you to more effectively use more powerful abilities.
The main thing to take away is not that Heal is suddenly an incredibly powerful tool. It isn't and is not meant to be. Rather, it's now a viable tool in the toolkit when raiding, rather than merely something to use when things are stable and boring in dungeons. You shouldn't be leaning on it, it shouldn't be a large part of your healing or usage...but it should be used now. It can provide value, essentially for free from a mana perspective. It's drawback is opportunity cost...it's a piece of time that you're not using to cast a more powerful spell. Most of the time, you can't afford that opportunity cost...but there are times when you should.
Casting Heal is like kissing your sibling. It's not generally recommended and feels a little shady. But in the right circumstances, especially with alcohol involved, it doesn't look half bad and everyone goes to sleep happy.
Pacing yourself is overrated. A common healer mistake, one that I am particularly prone to even now, is that mana must be carefully managed and paced so that it's parceled out evenly through the encounter. After all, you don't want to go out of mana, do you? Especially not in Clutch Time, when it's getting late and the clock is ticking down and the home team (that's your raid) is down by a few points?
The problem is that all damage really is created equal. Well, not precisely and I'll get to how it's not, but it's still a good generalized principle which I'll illustrate with some back-of-the-envelope math (I call it Casual Jerks theorycrafting).
Formulas Are Pro
This is your raid's effective health:
Health Pool(raid) + Mana Pool(healers) * HPM(healers) + Combat MP5 Regen(healers) * HPM(healers)
HPM = heals per mana point Combat MP5 Regen = every source of mana regeneration combined and placed in a standardized "per 5 seconds" frame of reference
(Bonus points to those who noticed I didn't reduce the equation to its simplest form. I chose not to just to make each element discrete: the literal health pools plus the healing done from the healers' mana pools plus the healing done from the mana the healers regenerate through the fight.)
There may be some slight alterations one could make to that (troll racial health regen for the win?), but that pretty much sums up all the health that the raid will have available to them for the entire encounter. We can view it as one large health pool that the raid draws from collectively. This is clearly not accurate in every way, as individuals do not share in the collective so losing a certain 180k health from that pool (say all the hit points of a particular tank) has a pretty major effect. But it works for the point I am about to make.
All of that health is what is available to you and, beyond making sure that everyone has at least 1 hp at all times, you just need to ensure that the boss health pool goes to 0 before that raid health pool goes to 0. Even if only 1 hp remains to the raid (maybe to an intrepid healer who dealt the coup de grace before being coup de graced herself), if the boss hit 0, you are the winners.
Your mana pool, as a healer, is one piece of that collective health pool and, with certain major caveats that I will detail in a moment, it doesn't matter when you use that mana pool, just so long as you do use it.
Let Me Repeat That With Pizazz
Let me put that another, more controversial way: it is better by far to go out of mana halfway through the fight (bearing in mind the caveats I am about to mention) than to wipe with any mana left in the tank. The reason for this is simple: your contribution to the raid's health pool is fixed for any single encounter. It is the amount of heals you can cast with your mana pool, factoring in the regen you experience during the fight. This and no more. Paced, not paced...it is virtually fixed (with yet another caveat, which is also coming in just a moment).
This means that whether you use those heals early, middle, late or carefully measured out over all those periods, your contribution is the same. Hypothetically, if you burned through your mana in the first minute of an eight minute fight, that means less healing for your other healers and they now have more mana for the remaining seven minutes.
More Fine Print Than A Predatory Bank Loan
Now before I get comments telling me what an irresponsible piece of advice that is, let me finally get to the caveats which are rather important.
All of the above only holds true as long as you are observing all of the following caveats:
Caveat No. 1: You are not overhealing. Well, duh. Any heal that is an overheal is wasting mana and reduces your fixed contribution to the Raid Effective Health. For shame.
Caveat No. 2: You are not causing other healers to overheal. Heal sniping (that is, rushing to cast an unnecessary quick heal to address damage that another healer has covered) is just as criminal as sniping in real life with guns. And if another healer overheals due to you, it's just as bad as you overhealing.
Caveat No. 3: Your zeal to heal during a certain portion of the fight is not leaving other healers at max mana. If you burn through your mana to such an extent that other healers aren't healing at all, and therefore sitting at mana cap, then they are wasting potential mana regen...which is part of their "fixed contribution" to raid health. Uh oh, that "fixed contribution" is looking less and less fixed. Didn't I have a caveat about that? Yes, it's coming soon.
All three of those conditions must be met for what I said above to be true, that it doesn't matter when you spend your mana and when you go out of mana. The moment any of those three aren't true, you're not doing it right and if you go out of mana, you've hurt your raid.
Fixed Contribution Caveat: Okay, so about that fixed contribution I kept mentioning. It's not really fixed, but I simplified it to make a point that I feel is valid. First of all, my claiming it fixed based on my cute little toy formula was based on ideal play: you are never overhealing and never wasting mana regen and you are exercising every cooldown to increase your mana regen optimally. People don't play perfectly, so that rather "unfixes" your contribution. Further, even if you played optimally, there's that pesky "HPM" variable in said formula. You can and always will adjust this on the fly and depending on how you adjust this (to balance with throughput aka heals per second), your contribution will be variable.
Okay, that was the caveat. The caveat essentially boiling down to "What I said before isn't really true." However, the overarching point is that there's a limited range to which you can change the raid's effective health pool based upon your stats and, whether we call it fixed or not, it doesn't matter when you use your portion of the raid's health pool, as long as the Basic Three Rules (given above) are met.
Okay, So What's Your Point?
So why am I mentioning this, in such a long-winded manner, at all? To say this: when in doubt, use mana. Don't be silly and spam your most mana inefficient spell from the start of combat until you run dry, but don't cancel a heal because you're unsure of whether you'll need that mana later. That damage must be healed...if not by you, then by one of your fellow healers. If you heal it, then a fellow healer doesn't and she will have more mana later which balances you not having that mana later. However, if you don't heal it and someone dies and the situation devolves and you wipe with 40% of your mana...well, my friend, you just paced yourself out of some shiny purple fancies.
It's tempting to try to use mana evenly over the course of the fight so that you run dry the moment the boss wheezes, falls over and says, "If it weren't for you meddlesome kids...!" before expiring. But since fights proceed in a non-linear manner and the exact time is not always the same, it's generally very hard to pace it out precisely.
From my experience (and we can file this in the "my experiences not necessarily typical" category), most wipes are not due to the healers running out of mana (when it comes to raids; heroic five-mans are another story when the healer is only just barely geared enough). Instead, most wipes (other than ones caused by failure to observe the fight mechanics) occur because the throughput at a certain moment was not sufficient between all the healers. No correctly handled raid mechanic leads to more damage than appropriately geared healers are capable of healing through. So, unless the mechanics were not handled correctly or people were not appropriately geared, these wipes are due to simply not healing enough: either not casting a heal when you could have or not casting a sufficiently strong one because you were conserving mana.
So the take-home, as far as I'm concerned is that it's better to err on the side of running out of mana too early rather than too late. It's better to challenge your mana pool than to play it cautiously. You must observe the three caveats laid out above, but as long as you have, heal away.
You may say I'm being a tad extremist about using mana with wild abandon, but there's a reason for that. I believe that healers are, by nature, overly cautious and it leads to less performance than they are capable of. This includes myself. I think it's worth harping on this, that a point of healing late in the encounter is not worth more than a point of healing early in the encounter. As long as your healing is not being wasted or causing another healer to waste resources, all healing is created equal. Therefore, so long as you are using all your mana and all your mana regen capability, it really doesn't matter where you use it.
Caveat About The Entire Post: None of this holds true for those rare encounters where the boss regularly reduces players to a percentage of their health or to a set amount of health. In this tier, that means Chimaeron and his little brother*Baron Ashbury. In those fights, obviously, there's plenty of chance to waste healing and therefore you do need to pace yourself. But that's one of those freak show gimmicks in which the laws of time and space don't hold true and you do what you must to survive.
Healers have long split stats into efficiency and throughput categories. Throughput stats were the ones that increased your healing done per second...the volume of healing you could push through any given time. Among secondary stats, these stats are/were spellpower, critical strike, haste and mastery. The efficiency stats were the ones that increased your healing done per mana spent...the healing longevity that your mana pool could sustain. These stats are/were mp5 (mana per 5 seconds) and spirit.
Mp5 is largely gone as an actual stat (though it exists as a concept, as things like a shaman's mana spring totem, Tyrande's Favourite Doll, the Corrupted Egg Shell and others essentially work as mp5 return), so we'll leave it aside. That leaves spirit as the single efficiency stat. And it's been a pretty important one for healers in the first few months of the expansion, as healing spells were far more expensive relative to mana pools than they were at the end of the Wrath of the Lich King expansion.
However, the logic for healers gearing through the previous expansion was expected to continue into this one. In fact, it seems too common sense to ever not be true: stack spirit until you feel that mana pool longevity is no longer an issue for you, then focus on throughput stats. After all, if you can last through a fight without being reduced to bandaging people, surely it's time to work on making your heals moar bigger?
I'm here to tell you that, while that may hold true later in the expansion, that almost surely won't be true in this tier of content. Even if you're healing heroics sitting at 90%+ mana and never running a risk of going out of mana in raids, it's unlikely you've outgeared the need for spirit.
The reason for this is simple.
For this tier of content, spirit is a throughput stat.
Spirit Is A Throughput Stat
Ask yourself this: In a raid, can you use your fast, inefficient heal exclusively? This spell is either Flash Heal, Flash of Light, Regrowth or Healing Surge depending on what class you are. Can you spam that spell as a solution to any damage that visits the raid?
The answer is probably of course not. (If your answer was "Sure I can," I'm happy to know Paragon's healers read this blog.)
In the final half year of Wrath of the Lich King, my discipline priest could use Power Word: Shield, Penance and Flash Heal (or it's hotter twin, Binding Heal) pretty much exclusively. I didn't need to resort to any other healing spells to protect my mana pool. That's a good reason to ignore spirit (or mp5 which existed as a stat then) and go for pure throughput stats.
However, right now, virtually all healers are constrained by their mana pool. The first raiding spirit benchmark, which is being met by many healers including yours truly, is being able to get through entire raid encounters without going out of mana, with efficient healing and intelligent cooldown management. This is being confused with a much higher benchmark, the point at which you should be switching from spirit to throughput stats (haste, crit and mastery--we'll ignore spellpower at the moment and get back to why a bit further down).
As long as you can't use your most mana-intensive and higher healing-per-second, your mana pool is constraining your throughput. That means that spirit counts as both an efficiency and a throughput stat. More spirit means better mana regeneration which means more of your better throughput spells can be cast. We are still in the era of spirit being the ultimate secondary stat...better mana regeneration will likely never be a throughput cap during this tier of content, as it was in the latter stages of Wrath. Better mana regeneration means getting to make a higher and higher percentage of your casts of the higher throughput variety. Fewer casts of Heal, Healing Wave, Holy Light or Nourish and more casts of your stronger spells.
So What's The Deal With Spellpower?
Spellpower is almost never a stat on its own (though weapons are the major exception) and it's not a stat we can explicitly stack as a secondary stat. It comes almost entirely from our primary stat of intellect.
Intellect is still our most important stat. This is because it is also both a throughput and efficiency stat. It provides spellpower (throughput), a tiny amount of critical strike (throughput) and increases our mana pool (efficiency, since there are key mana regeneration mechanics that work as a percentage of one's total mana pool). It's a more powerful combination stat than spirit and should remain so throughout the expansion and throughout the existence of World of Warcraft until Blizzard changes how stats work.
However, it hardly matters. Most of the time, you can't select spirit over intellect. Intellect, being primary, is generally budgeted separately from spirit, a secondary stat. Being primary, you cannot reforge out of or into intellect.
Gemming/enchanting are the only places where you could end up making a choice between them. Pick intellect. But pick spirit over everything else. It's a throughput stat right now. And an efficiency stat.
Wait until gearing has made the concept of mana the mere rumour that it was at the end of Wrath before you start ditching spirit.
(Pro tip: Remember to build a [Basic Campfire] in the middle of your raid. +4 spirit for free is basically #winning.)
Yes, I really just did commit that title atrocity. It amused me, which is the only way I judge success.
Stamina stacking has been pretty common for tanks for a while. Stamina was generally seen as the default go-to stat for any tanking class at least throughout the Wrath of the Lich King expansion. It was the best way to increase effective health, which was ultimate in tank survivability.
I think, though, that Cataclysm has changed that. The only benefit to increased stamina, really, was the initial buffer before dying. Health pool measures only one thing: How much damage you can take, without healing, before you die. That's it. That was useful when most tanks had between 20k-60k (depending on when in the previous expansion we're talking about) and hits could take 10-20k health. An initial buffer to allow tanks to take some hits before healers stabilized things was valuable.
However, Cataclysm has completely changed the landscape in terms of the "spikiness" of encounters. It's a combination of overall size of default health pools (the health you get from level and unmodified gear) and bosses having less damage potential per hit, generally, if mechanics are obeyed. Tanks are no longer at any risk of dying within two to three bad hits. That means the value of an initial buffer has been reduced massively.
Let's take an example. An average raid-ready tank will have around 10-12 gem slots available. Let us say this tank gems straight stamina (and is not a jewelcrafter, so has no access to Chimera's Eye cuts). At 12 gem slots, with a +60 stamina gem in each, this adds up to 720 extra stamina. Each point of stamina is 14 extra health, so the tank gains 10,080 extra health. The average raid tank has around 140k default health, so the extra from gemming pushed him or her to 150k or so.
What does this mean when fighting a raid boss? It means only this: the tank can absorb an extra 10k health before dying if he or she gets no heals. That's all. As soon as the tank falls below 140k health in this example (i.e. essentially the first time the tank takes damage), the value of the extra stamina is gone. After that, the entirety of his or her ability to survive until the end comes from the tank's own avoidance and mitigation and the output of the raid's healers. Total health pool has no more impact.
In Shocking News, Health Is Not The Same As Mana
Stamina for tanks is not akin to intellect for casters, because total health pool does not have the same effects as total mana pool. Even leaving aside the fact that intellect has other benefits (spellpower, most notably), there are key mana regeneration mechanics that operate as a percentage of total mana pool. Therefore, having a larger total mana pool has a direct relation to longevity of that mana pool...it's not merely an initial buffer.
Total mana pool would be nothing but an initial buffer if the only mana return that existed was MP5, as that would be a rough analogue to healing. Healing works as raw numbers, just as MP5 does, not as percentage of total health pool. Therefore, the total size of the health pool (in the universe of normal tank pools...no tank is going to be sitting at 30k total health nor is any tank going to be sitting at 1 million total health) has virtually no impact on the longevity of the health pool. Only things like dodge, parry, mitigation (armor, block, etc), tank skill in employing cooldowns, healer skill and healer mana really have significant impact on the longevity of a health pool.
Healer skill and healer mana are not within the tank's control and tank skill is not affected by gemming and enchanting choices. Only avoidances and mitigation are, which is why those should be the only focuses of gems and enchants (this can include mastery, of course, since tanking mastery largely seems to be mitigation-focused).
So Is Stamina Useless For Tanks?
Short answer: Yes.
Long answer: ...Yes.
(Okay, to be a little less glib, by "stamina" I mean the stamina acquired from gems and enchants. The stamina you get from your gear is necessary but that's something you get automatically. Thanks for reading. I'm going to end the piece on this parenthetical comment because I'm a writing rebel.)
