There’s a decent analysis of the prospective nerfs here.
As usual - this is PTR, things can change, not set in stone, blah blah blah.
For fury the patch notes look pretty unpleasant, since the buffs (raging blow being improved by war academy and the buff to mastery) seem to be outweighed by the nerf to heroic strike. I am slightly biased however, since I think the fury rotation’s dependence on enrage effects is pointlessly complex and difficult to work around, and there is no comparable difficulty in any other class that I can think of right now. It’s not simply a priority system based on procs, as every other class has, but you also have to manage your enrage state which is pretty ridiculous. Anyway, that’s a rant for another day. We are also hugely dependent on hit apparently (I haven't got enough fury experience in Cata to talk about that as yet, but it was true in WotLK and it makes sense for it to be true now).
The nerfs to heroic strike and cleave are also somewhat annoying for prot. I currently think cleave is a brilliant attack for prot right now – it hits hard but not too hard, it hits multiple targets, and it’s therefore great for AoE tanking. It also feels fun, for some reason - not sure why. Clearly therefore it needs a nerf for PvP reasons. This is somewhat depressing. I’ll probably still use it on cooldown when AoE tanking though.
The heroic strike nerf is pretty lousy, and makes the prot rotation complicated again – I will now have to try to decide whether heroic strike is better or worse than concussive blow or shockwave. I prefer the simpler prot rotation of shield slam > revenge > heroic strike, but it seems we are back into needing a six button rotation.
The buff to devastate, while probably not enough to compensate in theory, actually in reality is very good for me because I tend to lose my rotations under pressure and spam devastate mindlessly in panic. Now at least I will be suffering less of a dps loss. In addition, it’s a minor buff to the impending victory talent. Since you need to hit devastate to trigger impending victory then sub 20% you’ll basically be spamming devastate and hitting victory rush when it procs (which actually is surprisingly often – you are healing 7% of your health every 6 seconds or so). Spamming devastate is bad, but by making devastate more attractive, impending victory becomes less of a dps loss.
Level cap activities
14 hours ago