At some point in the future it'll be nice to have a certain 'fuzziness' to active and passive sensor detection. Detection of vessels is only guaranteed till a certain percentage of the sensor range against that TCS, with the percentage detection chance per increment (probably an hour?) dropping linearly till the maximum sensor range. Effectively, at the edge of sensor ranges ships could remain undetected or they could only be tracked very sporadically. This will extend to missile fire controls and the like. ECM and ECCM will modify the detection chance per increment for both active sensors and missile fire controls, but not passive sensors.
There could also be a modifier allowing you to trade between maximum sensor range and the maximum range at which detection is guaranteed while maintaining sensor cost and GPS. I think this might quite neatly solve the fighter issue - with active sensors modified to have a very high maximum range but a very low maximum range at which detection is guaranteed, fighter squadrons will eventually be detected by shipborne active sensors at long ranges, but they won't be tracked continuously and firing missiles will be foolhardy. You'll have to dispatch a destroyer squadron or two to investigate, so you'll be encouraged to maintain escort vessels for your fleets.
Of course, the main drawback as usual will be game performance degradation. On the plus side - more choices to active sensors design, a reason to bring along escorts, more vulnerable box launcher fighter squadrons, etc.