He should fight Reigns. It is by far the most interesting thing he could do.
That being said he will probably show up, throw verbal diarrhea in someone's general direction, maybe break his insurance clause with a quick Rock Bottom and then exit stage left.
Or "shockingly" not be able to make it due to some excuse but have a camera ready to do something via satellite.
Which would all still be more entertaining than most of the other stuff that will go on that night.