I'd rather see him on SmackDown!, but Punk anywhere but ECW is a good thing.
I think there may still be heat on him, but like most in the wrestling industry, it's not going to stop him from winning the occasional match, and getting merchandise put out and a chance to make the company some money. If Punk does that, I'm fairly sure he'll be able to beat the heat.
I wouldn't expect Punk to be a World Champion anytime soon, though.