#1 Baron Corbin
This is, without a doubt, the least popular choice. Sadly however, unless Brock Lesnar successfully cashes in his Money in the Bank contract at Super ShowDown, Baron Corbin will probably get yet another shot at Raw's top title.
WWE's next pay per view event after the show in Saudi Arabia will take place on June 23, which is just a little over two weeks after Super ShowDown. So, clearly WWE doesn't have a lot of time to put together their next show, which means that they'll more than likely do a lot of rematches, especially at the top of the card.
If Rollins is still the Universal Champion, he'd clearly be booked to defeat Corbin, so while the prospect of another match between the two won't excite many people, at least it'll lead to another win for the current Universal Champ. Or, maybe that'll be the show where Lesnar interrupts, cashes in, and wins Raw's top title.