This build works for everything but bosses for me.
http://us.battle.net/d3/en/calculato...TXV!bTe!aabZZb
All I do is switch to stuns for bosses, basically switch grenades and Impale to stun.
I had SteadyAim instead of SharpShooter until 50. Honestly this build feels way OP. You just shotgun blast stuff to the ground, use nades and bat to refill hatred, and then Impale single targets for max DPS.
This worked great all the way through nightmare. I really never had to change it at all except for stuns on bosses.

