This is kind of off-topic a little, but I agree with others that Punk is at his best as a heel, or rather, as an "anti-hero." It's no coincidence that he's always been at his most popular when he's a heel (since that's been the only time when he's had an attitude and an edge to him.) For the past few years, Punk should have been similar to Austin in that his attitude should have been one of "fuck everybody else in the locker room", yet still be willing to form uneasy alliances with people whom he shared a common enemy with. Instead, his attitude as a babyface since the Fall of 2011 has been your typical vanilla babyface who makes bland, cookie cutter promos much of the time and even ponders to the crowd on a regular basis. I mean, just a month or two after "shooting" on Triple H and challenging him to a match at NOC '11, he was joking around with him on Raw like they were buddies.
Even Cena himself still had an edge and played dirty at times after he turned babyface in October/November of 2003. He cheated to eliminate the Big Show at the 2003 Survivor Series and then cheated to win the United States Championship from him four months later, too. Just watch the last couple of minutes of their Wrestlemania XX bout (ironically, this was before Cena became a mostly bland babyface himself a year later):
