Well, the nerfs are in and to paraphrase Zapp Brannigan - the warrior nerfs are like the warriors' love - hard and fast.
You can read the full list in all its horror in the patch notes. Most of the nerfs reduce damage done by 17%, but some are different. I'm going to look at Fury and Prot since those are the specs I have experience of. Assume that all abilities are reduced in damage by 17% unless mentioned.
Raging Blow is reduced by 27%
Mastery is buffed by 50%
Slam rage cost reduced from 20 to 15
This is a very heavy nerf for raging blow. It may be that the changes to mastery (extra damage while enraged) balances this out, but looking at some napkin maths I doubt it. The effect on our rotations is hard to see at present - previously the fury rotation was
Raging blow (where available) > Bloodthirst > Heroic strike. It may be that raging blow drops from being the main nuke to being a filler.
I still can't see a place for slam - the problem with it has been that heroic strike is so good that rather than being a way to bleed off excess rage we want to hit it on cooldown. If we are doing that we just don't have the spare rage to hit slam as well (or at least I don't) and you therefore drop slam altogether. I've seen the suggestion that slam procs need to cost zero rage and I agree with that. On the basis that we have more rage now than we will have at any time in Cata (crit, hit and haste are higher now than they will be) I can't see this change making slam attractive.
Devastate is unchanged
Revenge is unchanged
Shockwave is unchanged
Shield Slam is unchanged at 85 (not sure about at 80)
The only ability that prot uses which was nerfed is heroic strike. It will be interesting to see how this plays out. Currently like for fury heroic strike is so good that it distorts the rotation - Shield slam > revenge > heroic strike with devastate being relegated to maintaining the debuff.
It may be that the nerf to heroic strike is enough to change the rotation but frankly I doubt it because heroic strike is simply so far ahead of devastate and shockwave at present. It should also be noted that the cookie cutter prot spec at the moment includes field dressing and blood craze, and so most raiding tanks (including me) haven't taken the war academy talent, which when maxed boosts heroic strike by 15%. The net effect of taking warbringer will bring us back to where we are now - that devastate is there just for the debuff (or can be dropped if you have the right kind of hunter pet with you), concussion blow is a stun only and shockwave is for utility and AoE tanking.
Oh, and finally, the rend nerf should pretty much kill off Blood and thunder as a prot talent I think!
How can anyone say that's bad?
1 day ago