I have Randy Orton winning this year tbh. Cena doesn't need to win the Rumble to challenge The Rock. Hell, I could even see The Rock outright challenging Cena to face him again at WM anyway.
Cena winning the Rumble coupled with Rock getting the definitie shot at the title at the Rumble combined with Punk having kept the title the whole time between then. . .just would seem too predictable and forced, not to mention illogical. It makes Punk pretty much a 3rd wheel, which makes you think why they didn't just take the title away from him at any point before then?
Anyway, I think it's gonna be Orton. Or possibly someone who gets a decent power push between SS and RR the way Sheamus did last year.