Let's just play along and say he does come back. What then? What does he do at mania? Does he somehow get into the title match, and if so, how? Does he get involved with Triple H? That's Daniel Bryan's spot. A tag match where he teams with Bryan against Triple H and Shawn Michaels? Michaels is just minutes away from the Allstate Arena today (as is Chris Jericho) at some World of Wheels convention. He could easily show up on Raw tomorrow. So if Punk does come back what do you want from him?
Batista said he's going to attack heroes. Here's how I'd play out the scenario.
1. At the start of RAW, Punk's theme plays. Then instead of Punk, Bad News Barrett shows up, and he's got bad news. (Just a swerve, if only because everyone's expecting this.)
2. Barrett is interrupted by Vince, who tells the people backstage to bring down the pedestal. Vince then gives an impassioned speech about Punk wrestling hurt for much of the last year. and that while he doesnt like employees walking out, it's a rough business and he doesn't want to see anyone get hurt, even Punk. He promises the WWE Universe that he and HHH wll try to get Punk back to fufill the remainder of his contract, when he's able to go at 100% again.
3. Toward the end of his speech, Punk comes out, with no music, standing behind Vince and grinning. Vince gets irritated that the crowd is drowning him out, until he turns around and sees Punk.
4. Punk comes out, and he says that he came out to say goodbye, in the only place that matters to him. He puts over some of the developing talent, saying it's their job to carry on the revolution he started in 2011. His body is shot, and he refuses to compromise it with painkillers or anything that isn't straight edge. He says he won't say no to "one more match", and says if it happens, he wants it in Chicago.
5. Batista comes out and attacks Punk from behind, laying him out. He yells on the mic that he promised to destroy all your heroes, and here's the first.
6. The next week on RAW, Punk invades HHH's office, demanding Batista. He points out that he was never eliminated by a legal man at the Rumble. Eventually Batista-Orton-Punk becomes a triple threat, with Batista ducking out of most of the Mania match between spots and leaving Orton and Punk to carry most of the action. Bryan faces HHH at Mania, and wins the right to face the winner on the post-Mania RAW.
Okay, enough fantasy booking. But I think Punk can be credibly inserted into the main event.