I voted mage as it's the only character I haven't completely dumped since classic.
In reality I'm not completely sure though. I will not make a goblin or worgen main for sure, but it might be my draenei paladin or if they warlock changes make them more fun, maybe even a lock.. or I will continue to do like I do now. 3 mains, no alts and with every patch, swap out 1 or 2 that are burned out or I'm bored of if needed.