Punk's ability to adapt though is amazing.
When he turned heel on Jeff, it was so slow and great. He was a heel because he beat Jeff. He grew resentful towards Jeff. Then he started pointing out everything wrong with Jeff, and how he, himself, doesn't have those flaws because he was straight edge. He was preaching to the crowd but he was still a face, wanting their admiration.
Then as time passed, he became a flat out heel. Generic almost, but his mic skills kept him above anyone. The Straight Edge Society was a good vehicle for him to just TALK. Things like Royal Rumble 2010 were really great stuff from Punk. The cult leader atmosphere he brought to himself, and even USED in the ring (where he'd say he'd accept someone in the straight edge society and then hit them) and the putting the right hand to the television screen... all good.
After SES, that's when I think Punk was losing some belief in his own career. The stuff with Nexus and Cena started off great, taking his preacher character to the masses but it fumbled because they had no faith in him. Some people liked his Orton feud and thought the matches were good but I didn't personally.
Now, he's a similar character to his heel one, but he isn't just saying he was wronged, he's brought to the surface that he IS wronged. From his chance at the top star spot to the title he rightfully won, he wasn't getting the respect he deserved. His grand entrance back in the company with his title, is him MAKING himself the star. He's a renegade star.
All this time, he's been changing his look too. From the long hair, to the beard, to the bald, to the short hair, to the blonde hair, to the slicked back greaser look. From the black hoodies, to the stupid Punk shirts, to the stupid Nexus/Punk shirts, finally to the first decent piece of merch WWE has ever put out.
Punk is great because when he changes his look, it isn't just the color of his fucking shirt.
