I'd actually enjoy some sort of 'Necromancer' kind of sub class that somehow utilizes dead enemies on the field; an ability our warlocks learned from understanding how ghosts use the light to reanimate our bodies. Charged melee attacks that kill make that enemy fight other enemies for a little while. Grenades are an area explosion that 'infect' enemies and slowly eat away at health. And the super could be raising all of the dead in any given area to fight for you for a short time.. Or able to revive a fallen guardian without being near him. Idk how this would work in pvp obviously but sigh I can dream can't I..