Honestly, if they moved John Cena to Smackdown for a year and brought him back, then I would say go for it at WrestleMania 28. I know that's a hella far away, but here me out...
With John Cena off Raw, Randy Orton would be the clear choice for the top face of the company. The fans are way behind him, and he has the potential to be as over as Cena (though he probably will never sell as much). Miz and Sheamus would probably hold down the top heel positions, and guys like Triple H and Chris Jericho could keep the champion busy for quite a while. Cena could boost ratings on Smackdown and give us some fresh feuds over there. Now, I know there's less chance of this happening than him turning heel, but that doesn't make it a bad idea. What I would do is have Cena tear it up on Smackdown for a year, win the World title or something, and stay the hell away from Randy Orton and the WWE title. You could even wait until next April/May's draft if you really wanted to. Cena would be the top of Smackdown, obviously, and you have Randy Orton hold the WWE title after the Royal Rumble, and you have John Cena win the Royal Rumble (making him a 2 time winner, something Vince wouldn't want to pass up). Then you have Cena look like he's gonna challenge Smackdown for the title, but after No Way Out's Elimination Chamber match, you have Cena attack Orton and declare that he'll be challenging for the WWE title at Wrestlemania. The promos leading up to it could all focus on Cena being the dominate force in the WWE for years, and Randy Orton's rise to the top. Orton could claim that Cena was always in his way, and as soon as he got him off of Raw he was able to become the face of the company. Then finally at Wrestlemania you have the two top guys in the company go at it for the WWE title.
I know it takes a lot of time and planning and it would be way in the future, but with Mania 27 only... 7 months away...I really don't want to see that feud happen in that time period AGAIN. I also don't think that Orton and Cena will draw that well unless it's built up correctly. But hey, if they're both faces, a Mania 27 match could work... I just think you'll hear a ton of people bitching about talent like Wade Barrett, Miz, and Sheamus getting passed up yet again for Orton or Cena.
