Right. They're trying to play it like 2012 was so bad for Cena but he just didn't win any titles. He still won a good chunk of matches and he never once doubted himself after losing to the Rock. He's always completely confident and that gets boring. Sometimes the hero needs to feel dejected in order for the crowd to start caring about him again. Heroes going through heartbreak and then bouncing back is interesting. A hero always being confident and never getting depressed or frustrated with his life just gets boring.
I'd have more interest in Rock vs. Cena II if Cena had to build his confidence back up. Nobody's confident all the time, we all get annoyed, frustrated or depressed with things going on in life sometimes and when we overcome that it feels like a big deal.
Now it feels like Cena just lied about having to win the first match(just to build it up) because he knew the second one was coming. At the time we didn't know that though and him losing the first match, falling into depression and begging the Rock to give him a rematch because he NEEDS to beat him could have been an interesting little story building up to the rematch.