God, does it really matter what match goes on last? So long as it's good and you enjoy it it shouldn't matter where the hell it happens.
Normally I would say it doesn't matter which match goes on last but for a big 4 ppv like summerslam you really wanna end the show with a bang. Well that is how WWE use to wanna do it now its pretty much a guarantee Cena will close out every ppv especially when he is champion.
Re: CM Punk vs. Brock Lesnar - THE BEST VS. THE BEAST
Brawck Lesgnarrrr has no chance in hell, bruh. He's a part-timer that managed to beat the shovel-carrier himself, HHH. Punk wins and proceeds go after Heyman and Axel gets in his way. This way, they push Axel to the main event, and keep the storyline going.
The King of Kings vs. The Sting of Stings
: And you can watch #WM31 #Exclusively on #WWENetwork for #9.99 , #Jawn
Compare this WWE to today's WWE and you can see why we're disappointed with the product.