Originally Posted by Apropos
This seems to be more of a Swordsage discipline than anything else. And I think(hope) that was the creator's intention:
I don't know about you, but I was pretty sure swordsages were the only ones who normally get supernatural maneuvers.
Although I would really just allow it to be swapped for any discipline the same way most of the homebrew disciplines are. Because, as the OP mentioned earlier, the discipline is very circumstantial and spreading out maneuver choices over different disciplines makes your character severely weaker.
It probably would be a Swordsage discipline. I suppose since this is getting added to The Age of Warriors book, I should maybe just throw in The Demented One's wording for alternate disciplines with the caveat that it should normally be applied just to swordsages.