I think that's how it's designed. I felt like the camera felt sluggish when I played the demo at Eurogamer Expo, but now I've had more than 15 minutes (count 15 hours before I had to come back to the real world and go to work) I've gotten used to it.
Yeah its a really bad port from consoles... I still love the game for the content but it could be so much better if they didn't seemingly design this for consoles and sloppily port it over.
I don't think it relates directly to anti aliasing but rather to framerate in general. Turning my graphics down lower increase my frame rate and decreases the moust problem so I just think its related to frame rate.
If anyone can get some data on it that would be great. I'm really just hoping they work hard and patch the game to fix this because it really detracts from the experience.