fist of all, removing points from imp sunder would be counter productive to increasing rage efficency. devistate is the ability you spam the most, and the most right off the bat, 9 rage for a dev is huge at the start of the fight when you have 10 rage, maybe 11.
also imp revenge, stuns.... a stuned mob does not hit you, does not give you rage.
anger management is worthless, if your having that huge of rage issues, put on some SBV gear and drop some avoidance.
if your going to remove any points, take the 2 out of imp demo shout, its nice but not nessisary and your having rage issues, so less damage in= less rage out
the biggest thing is when are you having such huge rage issues? and what gear are you wearing at that time, build diffrent sets, avoidance, EH, SBV.