Playing games like X-Rebirth, Evochron and Space Engineers you can either have your Inertia Dampners on or off. This really does give you 4 dimensions of movement. However with Star Citizen decoupled mode puts you on a slider and eliminates your thrust. It also removes your ability roll etc. Comstab turns you into a drift ship nothing more.

What I would like to see is comstab turn off your dampeners and then allow you to use W,A,S,D for Ascend, Descend, Strafe Left/Right. And your Joystick/Mouse for noral Pitch, Roll etc. Allowing your primary thrusters to still work for forward reverse. This would allow for true zero g movement and set you up for all kinds of crazy maneuvers.