I think this actually plays very nicely. It's not a heel turn at all, and personally, if you take the way it was recorded into account, I think the reaction to Cena is about standard. However, I do think it's a very good idea.
On the one hand, the match is over, the tapings are over, and it's just Cena popping up to promo the live crowd for a future taping.
Except of course it's not. It's Cena interrupting CM Punk's celebrations. It's Cena 'disrespecting' Punk again.
The thing that makes the whole Punk 'tweener' angle work is that you can see Punk has a point. He's actually right about a lot of what he says.
So this plays right into that. It's simple, but it's good stuff.