#2 Roman Reigns
Roman Reigns could be an unpopular choice here but he is a titanic name to headline the biggest show of the summer. Reigns teamed up with The Undertaker to fight the team of Drew McIntyre and Shane McMahon at Extreme Rules.
The Big Dog had a lengthy rivalry with Shane McMahon but it probably ended at Extreme Rules. Since Shane has already started a new feud with Kevin Owens, Reigns might need a new opponent at SummerSlam.
While the fans have been vocal about consecutive title opportunities of Reigns, it could be the right time to bring him back in the title picture. The Big Dog won his first Universal Title at SummerSlam last year when he defeated Brock Lesnar. Unfortunately, the title reign didn't last long as he had to relinquish it due to leukemia.
Though Reigns won the Universal Title last year, his last WWE World Title reign was three years ago. The Big Dog could be the right man to stop the incredible momentum of Kingston. Both Reigns and Kingston are exceptional performers and they could tear the house down at SummerSlam. If Kingston manages to secure a victory over Reigns, the former could prove his dominance as the Champion.