Max rank Demo Shout gives a reduction of 410 AP
Max rank Demo Roar gives a reduction of 408 AP
Max rank Curse of Weakness gives a reduction of 478 AP
All of those spells have talents to increase their effect.
With max talents
Demo Shout – 574
Demo Roar – 571
Curse of Weakness – 573
Max rank Curse of Recklessness gives an AP increase of 135. With Frailty, CoR gives no additional AP bonus. If you have a warlock in your raid that does not have frailty and is putting up CoR, you need 4/5 imp demo shout to cancel the additional 135 AP.
If that doesn’t seem confusing enough, boss AP acts funny. The damage output of a boss seems to scale much higher with AP than does an average player but the amount of AP a boss has is relatively low. The reason that 2/5 was accepted as the right amount of Imp Demo at 70 was because bosses were found to only have about 350 AP and 2/5 Imp Demo gave a reduction of 348 AP. This was found by testing boss damage output with different ranks of Imp Demo. The average damage output didn’t decrease at all past 2/5 which implied that the boss didn’t have any more AP to take away. Early in the expansion, Curse of Recklessness wasn’t often utilized in raids because people didn’t see the power of armor penetration and because there weren’t any tightly tuned dps races. If bosses had 350 AP before and CoR added another 135, you now had to reduce 485 AP. A fully talented Improved Curse of Weakness gave the same reduction as a fully talented Imp Demo – 420 AP – but it was rare to have an affliction warlock in a raid at the end of the expansion which is why you started to see warriors with 5/5 imp demo.
I started this post off with the different AP reductions, and that’s great to know, but the real question is, how much AP do bosses have now? I haven’t seen any testing (with the x-pac only out for a week, that’s not too surprising) but hopefully someone with a mind for statistics gets around to it in the near future. In the mean time, I won’t be putting any points into Imp Demo. It’s just not worth it for 5-mans where the damage output is rarely enough to be a concern.