I think both will swim!
I think they could both swim as faces, CM Punk I don't believe will be a long term champion, however I do believe with his natural ability and the fact he is SO over will get him long enough, I have said this before but I fancy a Punk reign to be similar to that of Bret Harts when he first won the WWF title in 1992, take on all comers and defend the title against anyone (midcarders and not so main event men ie JBL) on a weekly basis
Kingston has everything, he has the natural athletic ability like Shelton Benjamin although after listening to his performance on the mic on ECW in a Benjamin match he has far more charisma although he is nowhere near as powerful