#2 Nobody else seems like a WrestleMania worthy champion
Over the past year, there has really been a couple of actual main event stars who were consistently at the top. Before Daniel Bryan, AJ Styles reigned as the WWE Champion for over a year.
He has been repeatedly used in similar storylines against the likes of Shinsuke Nakamura and Samoa Joe, so much to the point where he needs to stay away from the title picture for a while. We have seen Styles in the WWE title scene since October 2017 and it is time for a break. A similar issue sits with Randy Orton.
The Viper is a 13-time world champion and isn't exactly a fresh face in the WWE Championship scene as well, even despite his heel turn. Jeff Hardy has just not clicked to the astronomical level he did so ten years ago when he conquered the world and won the title, with his current ceiling being just below the top contenders.
Mustafa Ali's time will come, having just arrived on SmackDown from 205 Live, but it is still too early for him. Joe is the only other superstar who could feasibly carry the WWE Championship into WrestleMania 35, but that ship has probably sailed. So by elimination, we are left with the former Yes Man.