Until there's a major, organic situation for this to happen, it shouldn't. It's all well and good saying "turn Cena heel!", but what's the plan for the month after the heel turn? For 3, 6, 12 months later? No storyline, on-screen or off, is currently big enough for Cena to turn heel effectively long-term.
I agree, but that just shows how big of a problem the company has at the moment. No one is at Cena's level in the fans eyes and when someone comes close they get turned heel and momentum gets cut off from that star.
The company is also screwing over Cena by this kind of promotion. Imagine if Rock never came back to be a band aid for Cena and mask the fact that Cena has already destroyed the roster of stars?
It is the only reason why I said CM Punk was even lucky enough to get that title reign as the Rock/Cena story was being built.
Compare this to when Hogan and Austin were the top dogs.
Savage and Warrior were guys who could have been competition for his throne.
Rock and HHH were being built who were seen as competition and on his level.
CM Punk and Orton are the only current guys on the roster who could be seen at his level, but he has already gone through them.
The other two guys are retired in Batista and Ege.
Thus the reason for bringing Rock back.