If they're going to have Cena win the title and face Rock at Rumble, may as well put the title on Cena at Summerslam or NOC. Personally I like the idea of Rock beating Cena for the title as no one would expect Rock to win the second match between the two of them, and then for Punk to beat Rock at WM would be huge. They have been building for Punk/Rock at the Rumble, but they could easily transfer that over to WM. Have Punk win the Rumble, and have the Rumble winner finally actually get a "MAIN EVENT' title match at WM for the first time since Orton in 2009. I don't think Punk needed to turn heel just yet if they were going for Punk/Rock at WM, as that could've happened after Punk won the Rumble as a face, but it could still work just fine.
What I don't want to see happen is this:
Cena wins the WWE Title at Summerslam
Punk wins the WWE Title at NOC
Cena wins the WWE Title at HIAC
Punk wins the title at SVS
Cena wins the title at TLC
Or anything of the sort. Either Punk keeps the title till the Rumble or Cena wins the title ONCE and loses it to Rock at the Rumble. Please no playing hot-potato with the title, WWE.