Re: Cena 36 - who's next to carry the company?
Firstly, Cena is 35-1/2 years old, not quite 36. Moreover, he merely had bone spurs removed from his elbow. Not exactly some kind of huge surgical procedure. Yes, his back and neck are a constant source of worry, but there's little evidence to suggest he's in the twilight of his career yet. He'll probably be wrestling well into his forties, so long as his body can hold up.
At the same time, though, Vince isn't going to literally wait until Cena is gone to start building somebody new up. As we've seen these last three years or so, there have been a few new pet projects like Sheamus, The Miz, Alberto Del Rio, CM Punk, Sin Cara, Daniel Bryan (you can say that they never anticipated him being so over, but he was clearly a highly-regarded main event prospect--why else would they give him the Smackdown briefcase 14 months back?), and most recently Ryback and Damien Sandow, among others.