#1 AJ Styles vs. Seth Rollins
When Styles first came into WWE he was a face during his first program with Chris Jericho. He didn't get the opportunity to face Rollins at that time, as The Architect was recovering from his torn ACL.
Upon his return, he immediately picked up where he left off, in a program with Roman Reigns. Meanwhile, Styles turned heel and battled John Cena. In the brand split a short while after that, Styles went to Smackdown Live while Rollins remained on Raw.
To have arguably the wrestler of the year for WWE in 2017 and the wrestler of the year for 2018 come to blows with one another would mean that fans see nothing short of magic between them. They have faced one another prior to their time in WWE, about 10 years ago.
Today, however, to see these men, who are now at the top of their game, face each other would enable fans to witness everything they love and admire about both of them.