The game clearly had some mouse acceleration going on, so I did a google search:
http://forums.2kgames.com/showthread.php?11423-Best-sollution-Mouse-lag
Used that as a template to get started. I'm not sure setting the first one to false doesn't solve everything, but I went through and tried to give everything equal settings in the event it didn't. Also set all the aim assists to 0. Not sure if that's for mouse/controller, but I figured it didn't need to be there. Only played half a level with it, but it seems much more responsive IMO. If anyone has better settings, I'd love to see them.
Wish Dead Space didn't encrypt the config file someplace, because I'd love to take a hammer to those settings too.
Copy and paste the ending section:
bUseViewAcceleration=false
fDefaultYawSpeed=150.000000
fDefaultPitchSpeed=150.000000
fMiddleYawAxis=0.8f
fQuickYawAxis=0.8f
fQuickPitchAxis=0.8f
fSlowYaw_Speed=150.0f
fMiddleYaw_Speed=150.0f
fQuickYaw_Speed=150.0f
fSlowYaw_Speed_Aiming=40.0f
fMiddleYaw_Speed_Aiming=40.0f
fQuickYaw_Speed_Aiming=40.0f
fSlowPitch_Speed=150.0f
fQuickPitch_Speed=150.0f
fSlowPitch_Speed_Aiming=40.0f
fQuickPitch_Speed_Aiming=40.0f
fMiddleYaw_Acceleration=0.0f
fQuickYaw_Acceleration=0.0f
fMiddleYaw_Acceleration_Aiming=0.0f
fQuickYaw_Acceleration_Aiming=0.0f
fQuickPitch_Acceleration=0.0f
fQuickPitch_Acceleration_Aiming=0.0f
fMaxLeanCollisionYawSpeed=40.0f;
fMinTimeForFullYawDeflection=0.15f;
fMinUserProfileSpeedMult=0.5f
fMaxUserProfileSpeedMult=2.0f
fUserProfileSpeedMult=1.0f
fMinUserProfileAccelMult=0.5f
fMaxUserProfileAccelMult=2.0f
fUserProfileAccelMult=1.0f
fMMGYaw_Speed=40.0f
fMMGPitch_Speed=40.0f
fAimAssist_YawFriction=0.0f
fAimAssist_YawFriction_Aiming=0.0f
fAimAssist_YawFriction_Min=0.0f
fAimAssist_YawFriction_Min_Aiming=0.0f
fAimAssist_Pitch_Friction=0.0f
fAimAssist_Pitch_Friction_Aiming=0.0f
fAimAssist_YawRate=0.0f
fAimAssist_YawRate_Aiming=0.0f
fAimAssist_MinDistance=0.0f
fAimAssist_MaxDistance=0.0f
fAimAssist_MinDistance_Aiming=0.0f
fAimAssist_MaxDistance_Aiming=0.0f
fAimAssist_MaxLateralDist=0.0f
fAimAssist_MaxUpwardDist=0.0f;
fAimAssist_StickyAimCurveSharpness=0.0f
fAimAssist_MaxFrictionDist=0.0f
fAimAssist_StickyBlendOutTime=0.0f
fMarsalaLookStickCornerMult=1.2f