I, for one, find a Tauren rogue plausible. A combat rogue. There are a fair number of Tauren pirates in the game, most prominently Fleet Master Seahorn and Mr. Smite. Pirates and combat rogues have a lot in common, not the least of which being that the second word in combat's description, after "a", is "swashbuckler."
Goblin druids, now those are improbable. Draenei warlocks would be truly bizarre.