Right now there seems to be almost zero opportunity for him to cash in successfully on Roman because of the booking of both parties involved. I can't lay fault at the door of HHH because even if Vince was still in charge I could see him being in the same limbo position albeit with more backing. It still seems like they're planning on doing Roman/Rock at Mania so unless they magically split the titles before then I can only see:
- Cashing in and failing
- Rock winning at WrestleMania then losing the titles super quickly via cash in perhaps the next night on Raw or in the following weeks.
- Cashing in for the NXT Title like they teased.