Overhealing

Note: I talked to a shaman after posting this and realized where I had gone wrong with the shaman numbers; part of it was ignoring earthliving weapon and another part was just a lot of bad information about coefficients. The maximal shaman case presented here is much lower than it ought to be, and the single target case with earth shield should be higher as well, with proportionally higher mana efficiency since the output should be higher with no increase in cost. I generally think that shamans are the most reasonable class in terms of their throughput and mana efficiency, and do not tend to extremes. Also it is very important to realize that when AoE healing shaman get much closer to their ideal scenario much more often than other classes, but that's sort of what this post is about.

Valithria Dreamwalker brings up a great opportunity to talk about something that is totally insane about this game, and that is the unbelievable imbalance between the amount of healing that the different classes can put out. I composed healing profiles of each class using my own base stats. Bear in mind this means that all classes other than discipline priests suffer somewhat because they would have better itemization for their own healing spells, but ultimately we end up with near the same spell power and the other stuff matters somewhat but is a bit of a wash.

This is what happens when different classes direct the maximum healing they can an Valithria, in a stand-and-"nuke" fashion, before portal multipliers:

That is pretty substantially imbalanced. Paladins do a good 50% more than discipline priests. Of course, discipline priests are basically custom-screwed for this task by having a lot of their best healing being dependent on shields, which do nothing for Valithria. But the few oddball facts about Valithria don't really swing the balance. When you look at the same numbers, but this time applied to a person who is actually getting hit and taking damage (shields and trigger on damage effects matter), it doesn't look all that different:



This is assuming proper glyphing and talent spec for the task at hand. The main difference between this chart and the last one is that discipline priests move up above holy priests. Now lets look at the chart of the maximal healing scenario, the case where the enemies do damage in a profile perfectly suited to you and you do no overhealing:



Wow.

We are faced with some simple facts:

• Paladins can heal for at least 10%, or as much as 50%, more than the next best healer and can more than double other healers even when circumstances are equally optimal for both
• Druid mana efficiency is so high that if tree of life did not reduce the mana cost of their spells, they would still be the most mana efficient healer, leading second place by a noticable margin and close to doubling the mana efficiency of the worst healers
• Shamans appear to be heinously bad at AoE healing; I'm going to have to check with a shaman friend of mine to verify this, because it's hard for me to believe it's actually as bad as the information I have makes it look

But if all this is true, why doesn't everyone use paladins and druids only all the time? Why don't these healers that show up so well on the charts beat everyone on the meters all the time? Given that neither of these things happen, doesn't it seem likely that there is something wrong with my math?

The answer is overhealing! Overhealing is basically responsible for healer balance. The fact that bosses can kill your tank in a couple seconds means that everyone overheals a bunch in order to make sure everyone is topped up all the time. Druids preempt damage by throwing HoTs all over, Paladins cast Holy Light on people who can only use two thirds of the hit points when their beacon target is at full.

On a recent night of lich king attempts, my healing per second while active was 3330 while a druid in the guild healed for 3218 per second while active. A pretty minor difference, well within the margin of critical hit caused error and the discipline priest actually came out ahead, so those numbers don't immediately seem to bolster my case. My overhealing was 26.6%, so my raw healing output per second was 4536. The druid's overhealing was 70.9%. Go look at some logs, that is not atypical for druids at all. That means his raw healing was 11058, about 2.4 times mine.

Right now, paladins and druids have overhealing numbers that are really through the roof. There is simply no way to avoid them. And most of the time, that's fine. They are as good at healing when more than half their healing is wasted as priests are when none of their healing is wasted. But of course not every fight limits healing with player max health like this, and the more damage that goes out, the more the imbalance starts to show itself. There are quite a few fights that I feel as a discipline priest I am simply a liability because of my inability to deal out the healing numbers required. Anub'arak comes to mind.

I'm not saying that discipline priests are underpowered, because I still think priests are some of the best healers. The fact is that Power Word: Shield, with's it's instant speed, usefully large size, pre-healing power, and ability to play well with other heals is such a powerful tool that discipline priests are very meaningful in most situations. And, of course, in the vast majority of fights the strongest healers do just overheal their power away, leaving them close to par with their weaker compatriots.

But with the coming of Cataclysm, Blizzard has indicated that there will be a shift to a slower, more thoughtful healing game. A game where you have to try to choose the right tool for the job and where overhealing is something to worry about because you could run yourself out of mana spamming your biggest heals. In a game like that, these differences are going to be extremely pronounced. When the tank is in danger of dying in 5 seconds instead of 2, healers will be able to opt to play the game where the tank is in danger of dying within 3.5 seconds by just leaving the tank at 70% of their health. Compared to what we are doing now this will seem downright relaxed. At that point, noone will have to worry about overhealing at all and that druid raider in my guild will simply be 2.4 times as good as me.

Obviously there will be some pretty substantial changes between now and cataclysm, and I think they will rework some of these things. But I really don't think they are going to turn all this over before the expansion releases. Druids complained at the end of BC that they didn't have Flash Heal, then blizzard gave them Flash Heal and druids simply didn't cast it. Then the druid Flash Heal was made somewhere in the neighborhood of 50% better than the priest Flash Heal, for 20% less mana, and most druids still scoff at it, while priests spam Flash Heal all day long. Remember when Wild Growth was released on the beta? It was a better single target heal than holy light. We are going to have to wait for a lot of iteration before there is any semblance of balance, and sometimes iteration just pushes more and more in the direction of imbalance.

With 5 seconds instead of 2 to die, the difference between big heals and little heals, HoTs and shields, instants and channels will really start to wash out. The difference between their power and cost is going to have to even out a lot as well. Without priests getting a really substantial boost relative to the other classes paladins are just going to be casting Flash of Lights as big as our Flash Heals for half the mana and doubling their effect with Beacon of Light while druids leave HoTs on the tank that outheal our maximum single-target healing. Ten man raids will simply be choosing between bringing a druid and a paladin to the boss, or a shaman and two priests. At least shadow is doing competitive dps.