I seriously feel like, if they do put the title on The Rock, he should lose it to SOMEONE NEW.
I'm not saying someone completely new (i.e. Seth Rollins) or anything like that but use Rock holding the WWE Championship to push someone to the fucking moon.
Have Dolph Ziggler announce he is going to cash-in his briefcase on Rock at Mania and then have him go over CLEAN. Have Daniel Bryan make The Rock tap out in the middle of the ring. Have Wade Barrett win the Royal Rumble and then challenged and defeat The Rock. Putting Punk or Cena over Rock does NOTHING for the company.
Cena is still Cena and Punk is still Punk. You take a guy who has nothing to lose and everything to gain and BOOM! You got yourself a superstar.
I don't think any of those guys have anywhere near the credibility to beat Rock clean and have the fans accept it. You can't go from wrestling Yoshi Tatsu on Superstars to beating The Rock clean at Wrestlemania in the space of a few months. That's when you start getting "bullshit" chants and the fans turning on whoever it is.
There is nobody else that has been built up enough or has anywhere near the credibility to do it other than Cena or Punk, and now that Punk is heel the chances of him beating Rock clean seem highly unlikely
Ziggler cashing in after a match and picking up a cheap win is definitely possible though
But then again there is the wildcard, THE RYBACK
Edit: Forgot about Orton, he is a possiblity I guess but Vince doesn't seem too high on him anymore
Edit 2: Also forgot about Bryan, probably the 2nd or 3rd most over guy on the roster behind Punk and Cena. I would love to see that match but again I doubt Vince would be high enough on him to do that