John Cena at WM 29. As much as I like The Rock, and I do, I disagree with him coming back and fighting at the Royal Rumble for the title. It cheapens the title to have a part-time superstar winning it.
Who should he drop it too? Eventually Ryback or in an ideal world after a prolonged build up Kofi (you could tell such a good story seeing as Kofi is his real life best friend in the company, if done correctly would immediately create a genuine superstar (which WWE desperately needs).
Wade Barrett (in a triple threat in which he isn't pinned)
I'm as big a Barrett fan as anyone, but we'd be lucky to see Barrett even appear at WrestleMania, let alone win a world championship anytime soon. Remember, he's accumulated a grand total of one WrestleMania appearance in a 2-minute 8-man tag team squash match.