The way things are shaping up, it looks as if we will be having a Rock/Cena rematch at Wretlemania. I can only hope that it isn't for the WWE title, but I have the feeling it will be and the collateral damage for this match is just too much. Let's look at the obvious scenario.
The Rock defeats Punk for the title at the Rumble. This is only a good idea if the Rock can work almost every RAW between the Rumble and Wrestlemania, but that isn't going to happen. I have the feeling that Rock will be put out of action until Wrestlemania by the Shield. There is way too much down time for the WWE title in this scenario. Also, the WWE could make a big star out of anyone on the roster by booking them to end Punk's title run. Why give it to the part-time guy that doesn't need it.
The next logical step is for Cena to win the Rumble match which is another big waste. The Rumble match is a transition from upper mid carder to bona Fide superstar. It only happens once a year and Cena certainly doesn't need this win. I hate when they use the rumble just to elevate a short term storyline like Cena coming back from injury a few years ago. Unfortunately, I don't see the company giving the rumble win to a Cesaro, Sandow etc.
I could live with Cena not winning the Rumble but then going on to win a title match at Elimination Chamber.
Here is a scenario that would shock the fans and doesn't have much collateral damage.
At the Royal Rumble,The Rock hits Rock Bottom for what seems like a title win and BOOM, the lights go out. Everyone is expecting the shield to interfere but when he lights come back on, the Undertaker is choke slamming the Rock leading to a win by Punk.
Imagine the heat by a split crowd leading up to Wrestlemania. The undertaker did it because he simply doesn't like the Rock and the fact that once Undertaker quit wrestling full time, he never got a title shot again, unlike the Rock.