I've not read much in the forums just yet, so I'm not sure if this has been brought up, but I do feel CM Punk was never involved with Maddox or The Shield, I believe Paul Heyman paid them off due to the fact he didn't believe Punk will make it this far on his own.
"The We Part" from Heyman might be manipulation on his part to have Maddox and the Shield think Punk is on it and agreed for their support in his match ups.
When Vince exposed the video footage of Paul, Shield and Maddox, Punk was escorted out. This can work on both counts, either Punk was escorted out so Brock can make his reappearance and/or Punk finds out Heyman has been paying them off to help with his victories. I think CM Punk might show face at some point in time and take on Brock since Heyman will side with Brock as he's still more Dominant than Punk would of been.
What do you guys think?
I would personally prefer Punk being a hybrid of both, Heel/Face so he has every reason to fight Rock, Cena & Brock