I was reminded of a feature of an old MMO game (City of Heroes) about 10 years ago that they implemented where players could create their own 'dungeons', sort of.

They gave players a number of preset dungeons where they could add different enemies to ones normally found inside the in-game dungeons. You could edit the names of enemies add NPC's and dialogue. Not sure about attack names.

It'd be something cool to see. Running through a Tam-Tara HM style dungeon fighting through the hellish of FF14 monsters only to find out the final dungeon boss is a squirrel.

It'd be cool to see but not sure how other players would think of it. Might give the more creative-minded players something different to try.