i think radar is just for radar dishes, if sensors are knocked out, they are supposed to stop spinning. or something.
i personally wouldnt mind having more subsystem linked damage effects. such as:
manuvering/rcs: ships loose agility when damaged or cant turn at all when destroyed
weaponbanks: player looses the ability to use individual weapons, and potentially looses ammo. also makes it possible to shot off external weapons. can self repair but ammo is lost until a support ship is called
reactor: causes a really big explosion when destroyed, but otherwise the ship is still functional
targeting: loose the ability to lock on as fast or at all
shields (they might be in already):, loose the ability to recharge shields as fast or at all
weapon battery: weapons dont recharge as fast
stabilizers: ship kind of forced into glide mode/conservation of momentum/angular momentum
afterburner: loss of afterburner performance or total failure