CM Punk is a great heel. He's straight edge, just go holier than thou, talk down to everyone who drinks and smokes, easy transition.
I don't think Jeff could work as a heel, simply for the fact that his whole moveset is based around popping the crowd, and he's not solid enough on the mic to really give a money heel turn promo. So even if they tried turning him, his high risk moves would still keep him popular.
Rey sucked at his failed heel turn for this very same reason.
When did Rey work heel?