As far as I know, Leap (the stomp knock-down skill) isn't bugged nor being exploited in PvP (PvE is another issue... Probably just nerfed in PvE). Its often used as an escape in combos after Vermin Swarm. However, when you know your opponent's hp gotta be low after the pwning you gave them, use Leap and it will finish the job for ya. If not then it'll knock them back and if you charged it while your hp was a lil lower than half, you're gonna get pwned.