I'm playing with the idea of using the names of Power Sets, Traits, SFX, and Limits as on-the-fly Distinctions & Limits if they can be justified within the narrative.
The idea is that if Wolverine's player uses XP to trade out the Limit: Heavy Metal for something else, the Watcher could still achieve the same effect by invoking SFX: Adamantium Skeleton as a Limit.
If that makes sense to you, then why not use "And what I do isn't very nice" as a Distinction? I feel that it is not any different than improvising Stunts, which are supposed to be grounded in Traits or Specialties.
"Will shall be the sterner, heart the bolder, spirit the greater as our strength lessens" -- an ancient expression of heroic will translated by JRR Tolkien