How about En-Enfeeble spells? Such as En-Blind, En-Slow etc. It would make melee RDM happy since its applied on weapon hit, and it would recover some of RDM's usefulness as an enfeebler similiar to a GEO.

Or if people prefer back line they could introduce the Dark elemental nukes such as Dark-Fire and Dark-Lightning? Like they had in crisis core? If i remember correctly they applied random enfeebs on enemies when used.