Like I said unpredictability doesn't equate to good, that's a fallacy I see people use a lot on here.
Something I think could work and would be good would to be to have Rock win at the Rumble, retain it at the Chamber and go into Mania as champ. At the same time you keep Punk looking strong and have him become more of a tweener in the weeks during the RTWM, perhaps by having him split from Heyman (so he can become Brock's mouthpiece which Brock desperately needs). Then you do Rock (c) vs. Punk at Mania one on one with Punk winning clean, they shake hands after the match and that's the end of their story. Punk becomes champion (and a babyface) again and gets a huge win and moment at Mania.
Ideally Cena would turn heel at the same time so WWE have a top heel but that obviously would never happen