Currently, sensing works on individual ships/missiles. As a result, big ships get seen first, small ships get seen last, and how many ships are grouped together in one area is irrelevant.
I'd like to float the idea of changing to a system where sensors detect the COMBINED emissions of whatever is at one location in space (be it fleet or giant alpha strike composed of multiple salvos), rather than the individual emissions. Sensor strength (for active) or sensitivity (for passive) would determine how far out you can see the blob, and sensor resolution (currently exists for active and could be added for passive) would determines when you start to resolve different contacts. Make this the basis of the tracking time boost to PD targeting, which can be arbitrarily adjusted to tune the effectiveness of PD up or down as needed for balancing purposes. Massive alpha strikes get detected earlier than smaller periodic salvos, and hence get hit more easily by PD. By reducing the effectiveness of alpha strikes, you make the ability to reload and fire again more valuable. The sensing changes would also have implications for detection of fleets, encouraging less blobbing if you're trying to be sneaky, and penalizing large ships less (from a detection standpoint) vs a comparable tonnage of smaller ships. It would also make a single ship operating alone harder to spot (at least relative to a giant fleet), which could open up interesting scouting opportunities.
Also, depending on how current sensing is coded and how it was changed to implement this, this approach might reduce game lag due to calculation of sensor detections. Without seeing the code I'm only theorizing, but if you performed sensor checking on a fleet vs fleet basis first, and only started checking fleet vs individual ships once fleets can see there's a blob out there, it may reduce processing time.
Thoughts?