The moment you mentioned feints as an example of options lost for "locking" movements, I knew your post will lead to Sui Generis

P). The feeling that I can't shake off, however, is that Sui Generis' system is so unique that no lessons can be learned from it about TW - or any other game actually that relies on a predefined pool of animations (which is every one other than SG, I think?).
Don't get me wrong - feints and parries the way you describe them are amazing. But I'm struggling to imagine them in TW3 as a "spontaneous" move, rather than an "independent action of itself". A combat "move". Like a light attack is a move, and a heavy attack is a move, the only way I'm seeing feints enter the game is as another "move". Say, "Shift+LMB". So from my perspective, locking you into an animation doesn't disallow feints, because feints aren't a spontaneous move to begin with.