Posted this in the WoW suggestions forum:
http://forums.worldofwarcraft.com/thread.html?topicId=18031098524&sid=1

I am sure I’ll get flamed, but here’s the actual post:

The logic behind giving Exorcism a cast time is there, or at least on the surface. I agree it needs to be included in PvP, with some sort of ‘penalty’, or else the up front burst damage could be brutal if left as instant cast. Giving it a 1.5 second cast time with the chance to instant cast off Art of War seems like an even trade off. Having to stand still to cast the spell will neutralize the Paladin just a smidge to take off the edge we seem to have.

Now, in PvE, especially in raiding, I am not quite convinced the mechanics need to change from instant cast. Yes, we get the upfront burst damage, but Exorcism is our least damaging spell in the long run. Every single recount or damage meter for any decent raiding Paladin will have Exorcism as dead last, and trailing quite a bit behind all the other damaging spells and abilities.

With the new Seal of Vengeance being the heavy hitter and seal of choice for raiding, along with its judging counterpart, I can see where the tradeoff may or may not be beneficial to our ‘rotations’, but I don’t see Exorcism as instant cast being a huge DPS booster. Not enough to justify giving it a cast time. Art of War, again, gives us the option of an instant cast by choosing between it and Flash of Light, but to me that is negated by the fact that we are using it far less in the 3.2 changes. Maybe that’s the intention, and if so, I disagree with the logic behind the decision, as I think it should still be an integral (albeit small) part of our DPS.

In PvP let it have its cast time, I totally agree with that. But in PvE, let it remain instant cast.