In my mind AW-style moves aren't about how you could cleverly manipulate an existing rule to arbitrate something, they're about intuitive pattern-matching on the fiction.
Agreed! That's why I think bluffing is Defying Danger using Int. That's intuitive pattern-matching between fiction and mechanics, IMO.
To me, Defy Danger is supposed to be about reacting to some specific fictional danger. Bluffing, on the other hand, is a character-initiated action to achieve some specific intent.
To me, bluffing is a seat-of-your-pants, bullshit-my-way-out-of-this one kinda thing, which sounds like a very reasonable application of "quick thinking."
I'm not talking about calculated persuasion or negotiation or anything like that. That's clearly Parley. I'm talking about a spur-of-the-moment effort to fast-talk your way out of a sticky situation.
Those don't feel similar enough to me that they ought to be pattern-matched by the same move. I suppose "does the NPC realize that you're lying?" could be a Defy Danger but I think what people mean by bluffing goes beyond that.
"Throw them in the pit."
"Wait! If you throw me in the pit, you'll never find out where the Circlet of Al-Ahad is buried!"
GM: ...The circlet of what
Player: Beats me. I'm just trying to stay out of the pit!
I realize this could be interpreted as the character having leverage there, but to me that's an illusion. The character doesn't have
leverage so much as he's trying to create
leverage out of nothing. If he can't sell this lie, he's in for it. YMMV, of course.