My idea of sub races is pretty much for aesthetic reasons for new comers and to pander to the RPers/Hardcore fans, so the differences can be a small as tattoos and just new skin colors (Maghar/dragonmaw/wildhammer) or kinda drastic (Revantusk/Kurenai).
I only went with "sub races" who are currently factions within the Horde/Alliance just for "logical lore" reasons...did not mecha gnomes, Demon elves, ect unfortunately, cause theyre not current factions in game, although I did find Leper Gnomes could work for the horde o.O. Sylvanas and a lot of her rangers in Undercity are forsaken blood elves, which is why I felt like they would fit. I used names like Revantusk/Kurenai instead of Forest trolls/broken Draenei because they are factions of those 'sub races' already in the horde/alliance...so why not be able to play em? As for the female versions of some of these...thats where Blizz comes in :P
@ro9ue
Micro transactions for sub races would make me cry >_< Bad idea lol. But yea I think Hozen could be shamans...dont know about Jinyu Pallys though.