Animation quality is up to whoever is in charge of art direction/animation. High budget games frequently have mediocre or lame movement and melee animation, and like you say there is definitely a pattern where eastern developers are simply better at this (obviously it's subjective, but that's how I strongly feel).
TW3 doesn't have bad animation and combat because they didn't have enough budget, it has bad animation and combat because the person in charge didn't think it was bad (and regardless of whether people like me disliked it, whatever they did worked for that game because it was a success and has legions of fans.).
It's like saying a michael bay movie has bad writing because of low budget. No, it has bad writing because the people in charge chose that script. If you took whoever is in charge of animation at platinum games and had them lead the animation for the witcher 3 it would have been dramatically better because that person knows what he's doing
It's interesting to see the difference in how quickly every part of the graphics in Netherrealm fighting games evolve compared to the animations. Which are evolving, but at a much much slower pace.
It's possible that the talent just isn't there yet, even if they're willing to put money into it to hire new animators.
And yeah, as you said, it clearly worked. And as someone who thinks good animation is one of the most important things in making a game look good to me, I can clearly say that I'm in the minority whenever people are discussing graphics, and bashing games that have superb animations in favor of others that don't move nearly as smoothly, but have much better effects.
EDIT: About Platinum, it's crazy to see them talk in devblogs about how they needed to hold back on the animations for gameplay purposes, and how, as animators, that hurts a bit. But then you look at the animations and they just look vastly superior to games that go for animation priority to the detriment of controller response, like Witcher 3 itself.
If Nier Automata is Platinum "holding back", other devs really need to catch up.