I'll be honest here, I only just started watched wrestling again. I don't know why everyone hates Cena. I haven't seen it.
From what I've seen (started watching wrestling again at SS), I think he's a great, charismatic wrestler. He seems to be a big guy, but can put on a great match.
I guess (same with rocky and stone cold) he has been shoved down the fans throats the last four - five years. I guess the WWE finally see it so they are embracing it. I guess this is why they're pulling for new faces in guys like Rhodes, Ziggler, Ryder and ofcourse CM Punk.
Also, the internet community (sites like youtube) are so far out of concept, they think he can't wrestle. Really? That match at MITB got a 5 star rating, Punk might have been in there but it takes two to make a good match. Cena can carry his own, which is half the reason why it was amazing. The other was Punk and his loud home crowd lol.