ATG is pretty good. I mean it is an instant 1300 burst most of the time in pvp (appx). But the problem is that without determination/without warning perks you must rely on the proc rate to refresh your stacks. In group pvp this can be very difficult sense you have 15 seconds to make a new proc. Basically on average I see myself proc in pvp on avg at every 5 sec. So if I flea form combat to heal I better hit the target in the next 10 sec which basically means I can't leave combat at all. I think it would be only fair that the barb have about 20 to 25 sec to hold stacks so at least I could heal a little if I am using ATG or bone shatter+upheaval combo. If not, at least don't loose all 15 stacks at one time sense it takes about 2 min to get all the way to 15 stacks as it is (if you don't have arcane marauder but you do have atrocity.) Everything else about the barb is alright though.