1) Cena loses.
1a) He doesn't tap, but nearly does. Bryan wins clean off a roll-up, or possibly bridging a German suplex.
1b) Orton cashes in, Bryan's spent after a lengthy match.
1c) As built up by the gauntlet match on Raw, Bryan has stamina (commentators sell this) and takes Orton to limit, making him tap.

2) Cena continues to be involved with Bryan and a heel Orton, leading to a Triple Threat match at NoC. After that, Cena may drop out to let Orton and Bryan feud solo.

3) Cena takes a break from the title picture after NoC, feuding with Zeb Coulter for being a bad role model for Americans (helping Cesaro get over in the process).

4) Cena enters another face/face feud with Bryan, leading to a rematch of their SummerSlam "classic". Punk might be involved in the build-up, but likely not in the actual match. They face for the title, where Cena finally taps clean.

5) Cena's at a point where being champion does nothing for him. Unless they need someone to keep the belt warm, he should stay in high-profile non-title storylines moving forward.

I honestly like the Cena vs Cesaro Feud Idea. I would love to see a match between the two.