I replied to your post about Cena staying face forever as you were in agreement with it. You said, "Personally, I'd like him to stay face forever. I just don't appreciate how much they limit him. He has a great personality and we see so little of it for the sake of public perception."
Now that we've established what I replied too, I was stating that he will get stale as a face FOREVER, no matter how you book him....anyone, whether it be Hogan, Austin, The Rock, etc., will get stale if they stay face forever. My reply is directed at that fact that you, personally, would like him to stay face. I'm telling you that he will only get more stale. I know he's stale now, duh....but it will get worse down the road....whether he goes back to hardcore rapping, standing on his head, break dancing, whatever: it wouldn't matter is my point.
Cena does need to turn heel at some point. After someone like Reigns or DB is given the preverbal "top dog" spot....he'll have to do something different.