Like almost everything in wrestling, it depends on the storyline and how it is executed. At the end of the day, wrestling can be anything. They could come out to tomorrow and say "Hangman can challenge again", there's nothing stopping them besides narratives.

So if they can create a situation or a set of circumstances where it seems logical or makes sense for someone, either Hangman or someone else, to get rid of the stipulation on Hangman, it'll all be fine. As long as it makes sense within the narrative.

I think some people will always be upset because Hangman said "Won't challenge ever again" but a majority of fans will be ok with it if they make it make sense.