I think aiming could be tightened up a bit to strike a balance with the acceleration (and perhaps the deadzone?).
I could get used to it kind of like how I did with Killzone 2, but I think it needs to strike a better balance like how Killzone 2 did with the high precision update to the aiming.
At the same time though, I think that some of it was from the frame rate (as noticed by going from near a wall where it runs smoother to the open where it starts chugging a bit).