I use the following rotation when "DPSing", mostly to maximize Storm's Eye debuff uptime.

I stay out of Defiance just to keep my threat low at all times.
1. Heavy Swing -> Maim -> Storm's Eye
2. Heavy Swing -> Skull Sunder -> Butcher's Block
3. Heavy Swing -> Skull Sunder -> Butcher's Block
4. Storm's Eye wears off -> Fracture, if not already applied (DoTs do not benefit from resistance reduction) -> Go to 1.

If the target does not require stunning, throw a Brutal Swing between hits as often as you can, same with Mercy Stroke once it becomes available. Use cooldowns - Berserk and Internal Release - together as much as possible, preferably after applying Storm's Eye debuff, and try getting a Fracture off before Berserk wears off.