I think part of the problem is people got tired of Vanilla Ice.
No, they tired of a thug with no sack. Real thugs don't fight the odds against mean guys, they don't give a shit and fuck someone, anyone, up. Note what sorts of reactions he got for the brawl with JBL at Judgment Day last year. Not only that, but they talk a LOT of shit. Cena hasn't talked some real shit in a very, very, VERY long time. It's all smiles and working up the crowd.