Cena is pretty bad. Just because his matches are given time and care, and he has the endurance to pull them off, doesn't make him a great joy to watch in the ring.
His stiffness always bothers me (not wrassle "stiff"; I'm talking his rigid, inflexible bod). His selling is generally embarrassingly bad. His pandering to critical fans by trying to do kewl movez does nothing for me. Anyone can add a new move to their repertoire. It doesn't make all other criticisms fall by the wayside.
His samey promos are tedious and his delivery sounds phony. His company man/I love WWE/The Universe/the sports-entertainment business is grating after 10+ years (and probably like 2+ years >_>).
He's an impressive man, who looks like a total goof. Just look at him. Of course some people won't be able to see past the jorts, etc.
I dunno. I still like some Cena stuff. And he seems decent enough, especially relatively speaking. But if we're talking wrasslin', dude's not great. There has never been a match where I haven't rolled my eyes because of him. Probably while he's "selling." Dude's a total ham.