Just got done playing PTR, my thoughts on Arms/Fury:
Arms
Its a little awkward getting use to the rage system being pretty much the opposite of what it was. I don't think it deserves the bad rap its getting. There are two things I'd like to see changed though:
Slam should be baseline. Maybe not in its current implementation but whirlwinding is so annoying to look at. They should replace slam in the talents with improved whirlwind which does pretty much the same thing slam does now but with aoe damage increase + rage cost increase per cast, therefore you have a choice between passive play, aoe damage or single target.
Sudden needs to be smoothed out. It's either awfully streaky or very sparse, and this could lead to wide variance in dps especially if it lands in a colossus smash (might be best to glyph Colossus smash for raiding). Maybe a higher proc rate/duration with a set ICD, or a way to accumulate charges. I like the thought of weaving execute into colossus smash, but the duration usually makes this not possible, or the fear of missing out on procs due to how streaky it can be.
As far as damage goes, Arms is pretty beast. I though obliterate was critting hard until I popped recklessness, avatar and colossus smash. 9k crits seemed absurd, I wish character copy was working, would love to give it a try on my character.
Fury:
Fury is actually pretty neat, and I like the changes. Its less intimidating to new comers but still a little more complicated than Arms. I like the way bloodthirst handles, and dumping rage isn't a concern I thought it be (probably because the wild strike proc was reduced to 2 charges instead of 3). My favored talent is Sudden Death, but for players looking for that no downtime action, Unquenchable thirst works nicely. I think it could have legitimate chance at pvp this expansion, Bloodthirst hits hard now and you can let off some quick burst with the proc.
I tried DK, mostly unchanged but Unholy's diseases seem to do more damage. Frost seems exactly the same to me but I barely played it.