You became surgical with it because you got used to it's quirks.
Back in early Uprising, the aiming with DS3 was terribad, but I got used to it overtime, since my brain automatically corrected for it's quirks.

I can tell the current M/K is accurate, just has a fuckton of input lag.
Swipe it left to right and see how long it takes for the game to react.

I'm no FPS vet or game dev or anything ... but my experience with KBM I find it just moves of it's own accord ... I can point at a dot, move the mouse right enough that would maybe move the pointer a couple of pixels and the pointer seems to do what it wants, jumping 20 pixels up and to the left rather than a few pixels to the right.

I don't think that could be down to input lag since the only input I've given is a small move to the right and the response I get is a large movement in the opposite direction with added vertical movement.

It seems more like the game is trying to push your aim off, like the opposite of an aim assist, more like when you try to push magnets together with the same pole facing each other and they skew away from each other.

That's my experience anyway ... and part of the reason I've hardly played since Uprising.