Well, as I said in another thread. It's interesting when you think about it. It's almost as if they've taken the picks for the next big face and next big heel and given them to Cena and Orton respectively to train and put over.
I'm not too sure Cena is gonna run over Sheamus, at this point I think the guy is too important to Vince's long term plan of building young stars.
I'm sure most of us expected Orton to have destroyed Kofi by now, but it still hasn't happened. I'm not saying I'm fully convinced that Sheamus is going to be picking up the title from Cena at TLC. But factoring in that he doesn't need to pin him, only put him through a table, it could happen. By doing this they're also keeping Orton away from the title for now.
And assuming they're going with Cena/Undertaker for Mania, I don't see either of them going in to Mania with the Title. We're due for a major first WWE Title win at Mania this year and I'm thinking there's a pretty damn good chance it'll be Kofi (my pick for the Rumble this year).
Even if Cena and Sheamus do a title program for the next 3 months or so with Sheamus getting at least a nice 2 month reign I don't see the harm in that at all.