My issue isn't with Cena himself. He can wrestle when he gets paired up with someone good. It's just that WWE refuses to ever let him lose legitimately. I also hate that they keep sticking with the same gimmick for Cena even though people have clearly turned against him. Cena is really the only guy I can think of who has literally never been a heel. Everyone else who has been in WWE as long as Cena has had to spend time as a heel. It's just sad that Cena is so immune. He might actually become interesting if they make him a bad guy. But he's just so fucking boring as a good guy.
He started off a heel. His feud with Taker was heel, and it was awful. Him beating Big Show for the US was the best thing that ever happened to him.
But let's be real, heel Cena would be what? Him turning on fans? That would suck.