Sure. My first thought on how it could work was simply having them tagged as Eredar and have unique customisation options. Basically they really just did give up their faction affiliation, or they could be ex-Legion now that things went bottoms up. Not sure DKs really work as a counterpoint; they're distrusted, but they were never as forbidden to begin with. Night Elf Mages are still Night Elves regardless of whether the Night Elf faction accepts them. They don't suddenly change race. Draenei are different in that it is not actually a race, but a faction and philosophy.