Agree with an awful lot of this. Not all of it, but a lot of it.
I always thought of myself as being one of the milder critics of Cena, but as you say, he's picked up an awful lot of defenders who cite a list of matches which were mostly against very good hands indeed, which kind of makes me feel less warm and fuzzy towards the man.
The one point I disagree on is the promo after the Extreme Rules match with Lesnar; I loved that. The problem was, WWE did not have the cojones to take him off TV and sell the effects of the match with Lesnar. The thinking behind the promo, after Big Johnny had hired a mercenary to see him off, was sound. That aberration was truly not Cena's fault.
I totally agree on the selling though, as well as his inability to put people over verbally much of the time. In fact he downright buries people on the mic far too often. Still, he gets that right from time to time, Bryan and Punk both getting respect in Cena promos of late. But then, it shouldn't be exceptional that the top guy makes his opponents sound worthy!
Anyway Sidg, I enjoyed this a lot; felt like the right balance in your tone of voice was there, and those are the best Sidg columns.