For Worgen’s I could almost see them using other species of dogs instead of using just the wolf as customization skins.
For the Draenei, yes I would love to see the Man’ari skin tones and horns for them. Maybe also use the broken skin tones as well instead of a whole new race. Light forge, just add a few more skin tones and eye colors as well, I can’t see Man’ari becoming Light forged but I could see Velen welcoming his former people back and unified again.
The main issue I have with Kelfin as a customization race is that racials likely wouldn’t change. As a result, we’d have an aquatic race that lives in the deep ocean and having the Gil part of the Gilgoblin race name because they have gills able to drown after several seconds in a pond.
Thus one of several reasons I’d prefer Kelfin to be their own playable race slot instead.
Unless they are going to magically add playable Ogres after all these years, I want an Ogre skin with its voice altered to sound like an Ogre on any Horde race.