If it hasn't been mentioned already the WoW enhancement shaman is kind of a RDM, minus the totems, magic dogs and obvious visual differences; hit guys with magically augmented melee weapon, shoot magics, limited healing ability.
Think it's a bit of a stretch to claim a RDM is impossible to implement when there's a somewhat similar example out there already.

Also, anyone else find that these 'new class/job' threads constantly make the current weapon-centric armory system seem like even more of a terrible idea? -_-