John Cena isn't a wigger and he isn't a Marine anymore. He is plain and simple, a walking shamWOW. Not only does his shirt look like a shamWOW he wipes the WWE clean making himself the almighty cleanser beating everyone there is to beat. He ABSORBS everyone in the company until there is no one left to beat.
Anyways, CTC was tried before. The "JBL is POOPY" incident is infamous. If Cena didn't go down in Summer of 2008 I seriously think CTC would have taken off. It would have been way better than Legacy.
As for Cena turning heel. It is always an option. Cena has been running out of gas for a couple months now I think, ever since he dropped the belt to Edge at Backlash of last year I think even the kids are starting to get tired of him. I might be wrong, but I think the day will come, the day when he turns heel and everyone can just STFU about "WHEN!?!?!"