Cena should be a heel or a tweener as his character shows so many heel traits, but they are totally overlooked, just so they can sell him to kids.
They also ignore the boos from a large majority of the adult audience. It used to be when a babyface started getting booed loudly, you'd turn him heel. Now, you just call him "controversial"....
Get off it, Snarf. The only ones booing are the guys. Chicks dig him. Kids dig him. And, to top it all off, he moves a shit load of merchandise. Hell, there is even a portion of hardcore fans that even though he isn't exactly their cup of tea respects the fact that he busts his ass to try and give a good show. Face it, as long as he moves a shit ton of merchandise like he does now, he isn't going to be turned no matter how much a segment of the audience boos.
Nowie's argument works because he is basing it on how the character is portrayed. He even understands that it simply is as it is because of who the WWE is marketing towards. But, you just had to bring the jeerers up.
The point you are missing is that most of those people booing are the ones who really aren't going to go anywhere. They will attend the shows, watch the PPVs, boo Cena everytime, bitch about how he is being crammed down are throats as a face, and then tune it the next night on USA and buy tickets to the next show. WWE doesn't have to listen to them. Hell, even I get annoyed at them sometimes because they should at least show the guy a little respect for giving them all he has. Hell, those guys are even more annoying than when the Canadians are being contrary just for the sake of being contrary.