#4 Seth Rollins
Seth Rollins can also benefit a lot by retiring one of the all-time greats in Batista. One way to book this could be, Rollins loses to Brock Lesnar at WrestleMania. A fatal four-way between him, Lesnar, Roman Reigns and Brock Lesnar is then booked for the championship at the next pay-per-view in which Batista wins by pinning Reigns after Roman and Brock obliterate each other.
Having the belt on Batista during the release time of Avengers: Endgame would lead to a lot of cross-promotion. Due to Brock's refusal to work a match on Raw(in kayfabe), a number one contender's match is booked between Rollins and Reigns.
Brock, however, shows up during the match and instead of taking out both men, takes out Reigns, allowing Rollins to pick up the win as a way to seek revenge against Roman. Brock and Roman then feud till Summerslam at which Roman defeats Brock.
Meanwhile, Rollins beats Batista at the next pay per view. He agrees to give him a rematch at Summerslam, provided Dave puts his career on the line. Dave agrees and the match is made. At Summerslam, after a hard-fought match, Rollins beats Batista and respectfully retires him. He shows respect to Dave who thanks the fans and officially hangs up his boots.