He has done this before. We just have to wait and see what happens. I think it would be amazing and so many fans would be happy if the Demon showed up and beat Lesnar.
Lesnar's part time schedule has also been killing WWE. It means something to have your champion on the show and obeying the kayfabe 30 day rule. The McMahons have claimed they are working to give fans what they want and I think they would want the Demon to take down Lesnar.