So the question is, which self buff should be used?
You can’t ever go wrong with having increased spellpower from Inner Fire. That’s an extra 1080 spellpower that you otherwise wouldn’t have had. I consider if the de facto self buff to use in most cases. The extra armor buff isn’t going to hurt either. Probably the default buff to use once our regeneration hits a point where we’re not struggling for mana as much. If I’m leveling, then I’ll definitely be using this for extra fire power.
Inner Will reduces the mana cost of your instant spells by 15% and it increases your run speed. I’ve noticed myself resorting to using Inner Will more often in some of the dungeons I do and leaning towards a heavier spell usage involving Renew, Power Word: Shield and Prayer of Mending. This sounds like its going to be the armor buff of choice for Renew Priests if the viability is still there. Anything involving lots of running? Yeah, I’m going to toggle this on as well.
Don’t forget about Inner Sanctum. I wouldn’t spec into it normally. But if you find yourself using Inner Will more than Inner Fire just to run around faster, then it might be a worthwhile investment. I don’t know if I find the 6% spelldamage reduction side of it useful. I guess it will come down to hard mode specific fights where it would be needed to help with survivability. 6% feels a bit low to me. I mean if they were going to combine it with Spell Warding, shouldn’t it be upped to 10% instead? Of course, I’m probably forgetting the fact that we have a massive health pool.
Yes, I’m positive there are going to be encounters where that 6% is going to make or break you. Anyway, when you’re leveling, go with Inner Fire. When you’re doing dungeons or raids, use the one that’s going to benefit you the most.