1. Cena has won the World Title 9 times IN AN ERA WHERE THERE ARE TWO TO WIN.The Rock won 7 WWF Titles when there was only one brand (and if you want to argue that Cena has still won more, The Rock also won 2 WCW Titles during the Invasion where there were 2 titles). This shows that The Rock is generally a more sucessful wrestler.
How in the world can The Rock be more successful due to the fact that he has won.. actually the same amount, 7 WWE championships and 2 WCW championships in a period where there were only "1" (due to the fact that he won 2 of them during the time where there were 2, as you noted) and The Rock has still yet to succeed holding them very long.
John Cena has held the WWE championship (ALONE only the WWE championship, that makes up for 7 championships, the same amount as The Rock has held of the WWE championship) for over 3 times the amount of time The Rock held them, therefore John Cena has a history of longer reigns, more retains, at the same amount of pay per views that The Rock had to face, where he would drop all the championship reigns before he even held them very long, The Rock's longest reign was 119 days, well John held it for 380 days once.
Combined, The Rock has held 18 championships, John has held 17, John's reigns lasted longer although, so you can highly argue the fact that The Rock was more successful, he was a tough guy to fight, but his reigns came immensely quick in a short period of time, where as John Cena held the championships for a long period of time through the last 5 years.
John should therefore be considered more successful due to quality of reigns > quantity of reigns.
2. Cena has held the titles he has for longer, but apart from those titles meaning less because there's two of them, he's also benefitting from an era where the bar in considerably lower. Instead of having to share the spotlight with guys like Austin, prime era HHH, The Undertaker, Mankind and other wrestlers many of us grew up with, Cena co-exists alongside second level guys like Orton, post-injury HHH, a HBK who doesn't want the title, Batista and Edge (never mind the fact that his competition in the main event is effectively halved as there are TWO brands).
The Rock didn't share the spotlight with prime Triple H, John Cena did, Triple H's prime (from my consideration) was during his Evolution time, and a decent period of 2005-2007 where John Cena did in deed make Triple H tap out, something The Rock didn't do, The Rock and Triple H faced in a period where Triple H wasn't in his prime.
John has also faced Undertaker in his prime, where he lost although, but it was out of John Cena's prime, which he hadn't reached yet, John is in his prime now, and has been in the past 2-3 years time, where he has beaten EVERYBODY,Triple H, Batista, Shawn Michaels, Chris Jericho, Big Show, Edge, Randy Orton, and Kurt Angle as well I believe, the list of people in their primes that John has defeated, exceeds the list of The Rock.
3. People actually watched wrestling when The Rock was at the top. He drew nearly double what Cena does (even in the year Austin was out, which is when the ratings hit their peak). People will say "oh but that was a more popular time" - guess why it was more popular? Because the wrestlers were better, people actually wanted to see them. Cena is good but he's destined to be consigned to the Hart/HBK chapter o the history books once the next wave of popularity comes.
The Rock being able to draw does absolutely nothing for the fact that John Cena is gonna beat the living crap out of The Rock, and then smash his ass through 3 tables like he did Edge.
John Cena makes the WWE a large amount of money, while the drawing wasn't the same in ratings, the majority of the time (even thought he was out) Austin was the reason for people to be watching WWE, John on the other hand, while he's hated by a lot, is loved by the majority of WWE wrestling fans.
Just because John isn't exactly a prime example of a great technical wrestler, he is a great example of a great worker and has the ability to put on great matches, and don't try to tell me otherwise, just because you don't like John, doesn't make it any less of a fact that he puts on regularly good matches.
And in the end, a match isn't won because you're able to make extra people watch, from a scripted stand point, X wrestler would still go over Y even if Y made the ratings go up by 1.5 or something.
4. Cena is a cheap imitation of The Rock. You see that lame "5 Knuckle Shuffle" move he does? It's a poor man's People's Elbow - those amongst us who liek to think pro-wrestling is supposed to be ultra-realistic will point out that both moves "suck", but at least the People's Elbow worked the crowd. Cena struggles to work a crowd - The Rock can get them to chant his name just by saying "they're chanting The Rock's name". That's what sets the greats of the wrestling apart from the merely goods. Sure Rocky Mavia got booed, but that was a footntoe to The Rock's career. For Cena to have won several title and still not be able to achieve the desired response on a constant basis marks him out as a weak pro-wrestler.
How is that a poor man's People's Elbow? it's nothing alike, and we've seen people do antics etc. before they execute a move, and even if John was to be an imitation of The Rock, that doesn't make him any less able to beat, or be beaten by The Rock, because just because John pulls off the same move, doesn't make it any less of a move to finish a match.
Good example is the fact that Undertaker does a leg drop on his opponents at times, Hulk Hogan does the same, yet Hogan's move is a finisher, Undertaker's isn't.
And again, being able to work a crowd, won't win you the match, besides John Cena's "you can't see me" move has the crowd chanting alongside, problem is that The Rock didn't have the crowd chanting alongside him when he did that.
Being a great entertainer, will never win you a match, it's that simple, John Cena's resume of beating great guys far exceeds the resume of The Rock, therefore you would consider John to have an upper hand, besides this is a TLC match, something John has experience in, beating the "king" of TLC's in Edge, The Rock hasn't even been in one of these matches.
5. The Rock has beaten Mankind aka Mick Foley aka the hardcore legend - at his own game. Cena may have faced the likes of Edge in "hardcore" style matches but The Rock wrestled in an era where rules took a backseat on a consistent basis. Cena (in his nauseating "face" prime) is a good guy who rarely if ever will cheat or bend the rules. Even as a mega face The Rock would take a chair and crack Hulk Hogan over the back with it. The Rock will do whatever it takes to win, Cena has his limits.
Because John didn't need to bend the rules, he defeated people cleanly, besides John has worked his share of hardcore matches against numerous different people, he's worked Hell in a Cell matches, he's worked TLC matches, he's never lost an I quit match, he's worked Last Man Standing matches etc. John is not out of any element when it comes to wrestling hardcore matches.
John doesn't have his limits, he rarely ever gives up, he always gets back up, Edge can testify to that, Randy Orton can testify to that, Triple H can testify to that, need I really continue?
Vote for the right choice, Vote John Cena.