Well my main is fighter with all the toys and tools available and my barbarian will have this ability unlocked tonight. It's current implementation is moronic and obviously bugged, I'd be willing to go as far as calling it exploitable. I can spam trip, sunder, stun and cleave at nothing to gain a charge which holds through instances... it feels so utterly cheap and it's cheating the game mechanics. Yeah, it's great fun once you activate and lay waste but it needs to be fixed. You should actually have to do something to activate your epic moment, in it's current state they could just as well give you a charge every two minutes.