In a recent interview Edge said he thinks he has about two years left in the business, and I don't see him getting 5 or 6 more title runs before he walks away. If he ever does return, it will probably be in a Stone Cold style, where he's not a champion, but he's used to get ratings and put other guys over. Triple H is a 13 time champion, but I don't see him getting too many World Champion shots with the remainder of his career. I see one good one left in him, but for the most part his place is to put the other guys over. Now, Randy Orton is wicked good, but he's never going to be the face of the company while John Cena is around, and that's just bad luck and timing for him. He'll get more title shots as long as he sticks around, and I'm looking forward to all of them. As for the Undertaker, if he gets another title shot (and I would be surprised) I think it will be his last. I see his time in the WWE coming to an end quite soon. Out of the guys you suggested, I think John Cena will retire with the most amount of title runs. He's already at...9? Yeah, I think that's the right number. But he's got years ahead of him, he's in his prime, and he's going to be the face of the company for a long time to come. I would give it a few more years and you'll start seeing him fade into an HBK role, where he's a legend who puts other guys over, while still staying on top of the main event card. But I can easily see John Cena beating Triple H's 13 title reigns, and possibly even surpassing Ric Flair and becoming the new record holder. I'm not saying I'm super excited about the idea, but I can see it happening.
As far as some of the talent that coming up on the main roster now, it's really impossible to tell. Guys like Kofi Kingston, Miz, and John Morrison have a ton of potential to be 10 time World Champions, but you never now how they'll play out. They could just as easily burn out and fade away into nothing. And while all of them are phenomenal athletes, I don't see Vince putting the company on their shoulders.