Heyman and Punk will carry this feud on the mic, and I expect Lesnar to make at least one more appearance on Raw (the go home show would make sense) before the actual match at Summerslam.
Everything about the build to Punk/Lesnar has been gold so far. Paul Heyman has always been a mentor, best friend, and somewhat of a father figure to CM Punk, so his seething hatred for Heyman and his betrayal is understandable. The dueling promos and personal jabs between Punk and Heyman have been fantastic so far, and Heyman's delusions for wanting deserved credit for Punk's year long+ WWE Championship reign is a great way to add more fuel to the fire.
I've mellowed on the size difference conundrum between Lesnar and Punk, and a lot of that has to do with me really wanting to see this match. Ironically enough, with help form Heyman and Punk on the mic, the size difference between Lesnar and Punk is one of the main attractions for this match. It's the classic David VS Goliath battle Punk alluded to in his promo tonight with all the talk of defeating and slaying monsters.
With all that said, the size difference between Lesnar and Punk is still something to think about. You can't have Punk beat Lesnar with the Anaconda Vice. A legit UFC Champion losing to a submission from a pro wrestler would flat out destroy Lesnar's character. The GTS? I dunno. The big question is, could Punk actually lift Lesnar, and land the GTS? Again, it's something to think about.
I expect the booking of this match to mirror Cena VS Lesnar from Extreme Rules last year. Punk will take a nasty, brutal beating, making Lesnar look like an unstoppable beast in the process. Punk will get in a few shots here and there for survival, but Lesnar will continue a relentless attack, mauling Punk into the ground. And if Punk manages to pull out a victory, it'll be because he hit some luck Hail Mary shot out of nowhere.
As far as a winner goes, I think Lesnar will take this. I honestly don't expect Lesnar VS Punk to end with one match. Maybe the rematch happens at Wrestlemania 30, or somewhere else before that. If Lesnar wins, he'll have the momentum going forward. If Punk wins with luck, then Heyman can brag about Punk's win being a fluke, and Heyman could go the route of goading Punk into a rematch.