The reason I don't think Cena vs. Rock II will happen this year is because there's been no build for it. And I doubt a couple of months will be sufficient for the rematch. Remember how much Rock vs. Hogan II stank because it was put on a B-PPV just before Mania with no build. Now the rematch here would happen at Mania, but still there'd be little build up. Also they'd start a feud between Rock and Punk but end it abruptly? There is NO WAY Rock will be in a triple threat at Mania.
Rock vs. Punk will happen at Mania, NOT the Rumble. But Punk will cost Rock the title at the Rumble. Now just who defend the title at the Rumble? Can't be Punk because it'd be stupid to have the same match at Mania a couple of months later. Doubt it'll be Ryback since he's my Rumble Winner prediction. Cena, again the problem arises in that it's too big a match to give away without proper build up.
That's why I've been saying Ziggler's gonna win the WWE Title soon, maybe even tomorrow.