Increasing sensitivity (of the mouse) doesn't help; I of course tried that. Increasing the sensitivity actually makes matters worse, not better: it doesn't eliminate the "deadzone" as you called it, thus makes the overshoot more extreme because the response is more aggressive when it finally comes.
Your reply almost makes it sound as if this was intended behavior, and I honestly can't understand why it would be. Who would drive a sports car with anything but a tight steering column? I haven't acquired any patch yet, so I will investigate that.
I just now tried it with the patch, which adds the different mouse interface style, but that wasn't the part of the patch that helped. Was the "deadzone" setting always described as "Joystick/Mouse" even in the release version? I had been under the impression that the deadzone setting - not that I actually understood what it was - was specific to joysticks only. I noticed in the patch version, in any case, that it was described as applying to both, and it had been set to the third notch all along. I set it to minimum, and that seems to have helped. There still seems to be some sluggishness in initial response, but not as substantial (as you might expect if you knew that setting affected it).
What purpose does that deadzone setting serve? I'm confused how it would be useful.
I also tried the FreeSpace style interface. I would prefer that, I think, if I could also invert the vertical controls to match the WC style. The cursor displayed in WC style doesn't really seem to serve a purpose and is a minor visual distraction.
I actually had bought a cheap(?) $10 Splitfish brand wireless game controller recently, having no idea what I would do with it but thinking I should finally have one (never owned one for a PC). I regretted it when I opened it, since because it's wireless it uses batteries, and six of them! So now here's this game that actually can use the thing. I guess I'll have to replace my worn-out AAA NiMH batteries and try the thing out. I'll also try the keyboard controls, but I'm pretty fumble-fingered so I won't make that a habit.
And regarding the deadzone, this is actually the first time I saw a game apply that kind of setting to mouse controls as well. You're right, normally it only concerns joysticks, and I can see no immediate reason why it should apply to mouse movement at all.
I believe, however, that this is a drawback of the Freespace 2 engine itself. There's drift to the control, so it's not so much that you PUSHED it too far, but that it keeps going after you push. It's a crying shame, especially in the case of ships that are supposed to have really tight controls (like the Arrow). Sensitivity and dead zone have nearly no impact on this. No matter what you do, if you release pressure on turn, it will always drift at least 3 to 5 degrees farther than where you stopped unless you were hardly moving at all when you let go.