1. Turning limit. WHY? this is an FPS, not an RPG, I understand you guys have put in the whole turning limit to mimic the orbit/tracking mechnism in EVE so that heavies will "turn slower"... but you have stepped out of your line. The moment you touch basic things like aiming speed, you have stepped on the toes of the FPS players and into the boundary of "too much". This is an FPS first, don't turn it into an "RPG".
Suggestion: (strongly suggested)
abandon the whole concept of "turning speed limits".
Alternate suggestion: (something you could do if you have the time)
have two "cursors", one is without speed limit and will move the camera without delay, but there will be a separate crosshair that controls the gun aim (this will also affect the gun model) will slowly "catch up" within its speed limit to where you are looking at (the first cursor). This way you get to preserve your game design concepts (slow turning for heavies/turrets) but won't make the game feel laggy.
TLDR: control->camera without speed limit, but the gun aim will follow with their own limits. (so if you turn very quickly 180 degree, your camera will turn very quickly without any speed limit, but you will see your gun turning slowly to catch up. If you fire within this catch up period, you will effectively see the gun spraying bullets along a trail as it tries to go to the centre of the camera.
2. Mouse control simulating joystick - just don't.
Mouse users need raw input. Period.
This should be the benchmark you guys should
aim to achieve.
http://www.youtube.com/watch?v=Ckv95eHdzTYMy point is that you need the LEAST amount of filters/smoothing/whatever be applied to your input.
We want RAW input to camera control, nothing more. This should be a top priority in your game design because this is what allows the FPS skill game to be present in your space MMORPGFPS. You don't mess with the basic FPS mechanics.
The control input to output should be perfectly linear (no acceleration, no smoothing) because this is where the skill game is at. <---this also applies to controllers. take away your smoothing and acceleration bullshet.
3. Framerate / performance issue. This influences the aiming. Fix this ASAP. First you need a
high framerate. Secondly you need a
consistent framerate.
4. Hitboxes detection. Nothing I can add to, just fix it. How can it be messed up in the first place?