Sadly. To pull off this build you have to be a pretty dickish person because this build requires you to...
The only ability that allows you to actually do some damage against some of the more OP classes in PvP is WoTB: Insanity. Unfortunately, it only has 15s worth of duration on it, refreshing WoTB by relogging is possibly the only way to have it on "100% uptime".
This is the build:
Killing spree is just there to give you more CC. Ultimately, you want to be able to do a crit on each rend, which with insanity is almost always a one shot.
Try playing around with different skills if you feel this can be improved.
Take note that with WDs. If they decide to SW their !@# outta your rend. Rend their dummy bodies to break them out of SW, use your superior MS to chase them down and rend again.
For Monks, SSS and Serenity are a pain in the $%^. Try to lure them into emptying their skillbars, then rend them down.
DH's aren't that much of an annoyance as long as they don't spam SS.
Get used to the range of wrenching smash. If they get close enough. Wrenching smash> Overpower> Rend.
Take note, Ancient spear instead of Overpower if playing against ranged classes.
P.S. Oh yeah, you could try Skorn with this build, but the extra 10% CC from shields helps so much. Try mixing and matching different abilities, you might find a variation that beats this one.