The mana regen nerfs: why

[Nasanna]

I found this on the official WOW forums discussing the changes to mana regen in the next patch: http://forums.worldofwarcraft.com/thread.html?topicId=14990765234&sid=1&pageNo=14#263

The reason these changes have to happen are quite obvious. If they're going to move to less-spammy fights, druids and priests with spirit will dominate paladins and shaman without. As soon as you move to a situation where you actually CAN pause for more than a couple of seconds priest and druids regen spikes, where paladins and shamans stay static.

This doesn't necessarily make druids and priests overpowered, but it makes it unbalanced. If they balance it around paladin/shaman regen, either druids/priests have to keep casting constantly, or else they get to make use of the 5sr. How frequently they get to make use of the 5sr regen is dependant on:

How frequently the target avoids hits/resists damage.
How frequently they get clearcasting procs.
Who else is healing, and whether they land a heal.
Whether they have cooldowns up like inner focus.

When you factor those unpredictable effects in, you can't make a strong model of priest/druid regen over the course of a fight, so you can't design a fight that will make a class go OOM if they play poorly, or if they undergear the content or whatever. You can only make a fight that challenges healers to not screw up.

Paladins and Shaman have pretty much static mana regen. They have some cooldowns to get mana back, but nothing as variable as the 5 second rule.

If you base your fights around paladins and shamans going OOM, you need to base your fight around priests and druids going OOM at about the same rate. And then when you take into account a streak of tank avoidance, letting you cancel heals, clearcasting and inner fire letting the priest hold off on spending any mana for 15 seconds, that lucky streak translates into a boatload of mana regen that the paladins and shamans have no way of lucking into. In this respect, it makes fights on average too easy for those classes with higher in combat mana regen.

If you balance it around the average mana consumption, then when you have a bad streak where you can't cancel more than every other cast, and you don't get clearcasting at opportune times, you're going to run short on mana early.

The problem is simply, the 5sr adds too much variance into your regen that non-spirit classes don't deal with. Blizzard wants to make fights that challenge your mana pool, but they have to be able to model what your mana pool should look like over the course of the encounter. When luck based factors can greatly affect that, there's no way to model it.