#1 Roman Reigns vs Dean Ambrose
Would booking Dean Ambrose to turn on The Shield once again at Fastlane be a lazy move creatively? Sure, but it would also set up a potentially mouth-watering clash between Dean Ambrose and Roman Reigns at WrestleMania, giving the former a big send-off match, and the latter a big feel-good victory on the grandest stage of them all.
The two men have a long and well-documented history together, but despite that, they have only once fought each other on PPV, all the way back at Survivor Series 2015, with Reigns coming out on top.
Of course, the WWE could be extra brave and have Reigns turn on Ambrose as an act of revenge for Ambrose betraying Rollins back in October.
Either way, the WWE should definitely pull the trigger on this match-up, and plant the seeds for it on Sunday night.