#4 John Cena
Can we all agree that the match at WrestleMania was not the dream match we were waiting for? After years of anticipation for John Cena vs. The Undertaker, we finally got a squash match that ended almost as quickly as it began. I think there's bound to be a repeat down the road, for certain.
What better stage than SummerSlam for this epic rematch? If Cena's schedule allows him, he could come down and take on The Undertaker in a match that could actually live up to the expectations of fans. The two men could then engage in a battle worthy of being a dream match.
While neither man is in his prime, they're both masters of psychology. They can tell a fantastic story in the ring even without having to resort to flips and dives. Much like the Roman Reigns match, this could set up a rubber match at Survivor Series or WrestleMania.