They're not going away from PG anytime in the near future. It's too expensive in terms of lost sponsor/advertising dollars to leave TV-PG and go TV-14. As it is they're TV-PG and will stay that way.
Having said that, I, too, am seeing more aggression and a bit more realism from the characters in WWE, particularly the heels. For what it's worth, I believe Punk had a legit cut to the top of his head (blade jobs are cleaner and easier to stitch up, usually not requiring staples, if they require any stitching at all). The fact that he was immediately tweeting about it and it's been so widely discussed among the fanbase suggests that WWE is going to be worrying less about blood. Remember, in the end, they're supposed to be professional fighters and CM Punk has led the way in this, followed closely by guys like Daniel Bryan and ADR.
As usual, it's the heels that drive the bus in innovation in WWE (not just WWE, they do it in TNA, ROH, and every other pro wrestling promotion, as well; we're just talking about WWE here). Hopefully, this is a sign that WWE will show a harder edge on its characters.
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