Going to lay out an idea that i think something definitely needs to be done:
-Cena isn't turning heel/going away from the main event any time soon
-WWE needs to elevate some younger talent
-Stables can do this
-This could get another interesting storyline out of him, instead of his corny feuds (not saying he doesn't have good feuds)
-Have Cena lead a stable, with two younger stars, Youngster X and Youngster Y [Will be referred to as 'X' and 'Y' from now]
-The stable would be in a similar mould to Legacy, but with Goody-goody Cena type faces
-The superstars don't interfere on each other behalf unfairly etc. like most stables tend to do, because the two younger guys follow Cena's values
-But they would, of course, help each other out, if heels ganged up on one of them
-Have the stable go on for a few months, with X and Y both winning more matches then before, leading up to X winning the US/IC belt, with Y by his side.
-Y slowly grows jealous of X becoming the more successful one, and starts to think Cena favors him.
-Because of this Y has a slow burn heel turn, resulting in him injuring X and costing him the title
-This causes Y to feud with Cena, elevating him to the main event
-Y goes over Cena in this feud (albeit, not cleanly, as he's a heel now)
-X comes back, and wants his revenge on Y, setting up a main event feud between these two
-A new heel, and a new face have been elevated to the main event