I see nothing wrong with BM burst in its current state, class is meant to be bursty, stampede needs to be fixed to actually be 25% if thats how it is to be intended, but thats basically it, its already suffered a nerf in the form of a 25% nerf to Rabid. PVP is balanced around Arena and BGs right? Excluding duels completely, BM hunters are easily countered in arena and can rarely ever take down any class too quickly provided their opponent is slightly skilled and ready for what's coming. From my experience bm burst is on Par with warriors and demonology locks.
I think overall people are seeing way too many BM hunters just pressing one button in duels to win, without considering their real presence in arena and rated bgs.