This premise(?) would presume that Khan is not stumbled upon and thawed, but time travels back after being 'reborn' (I really hope not), to settle things.
A villain time-travels into the past and exacts his revenge for something that happened in the future. I think I've heard that one before.
Which is why I hope that's not the case. I'm just putting out a possible reason for why BC would no longer look like traditional Khan if he is in fact Khan.
Nightowl - Agreed. I have long believed that BC was just a plot device. I eluded to that in one of my earliest posts for this film.