This is my favorite definition offered so far.

So for example, sensor boats. I considered them an exploit because they invalidated a lot of other intended mechanics.

1) Starbase Sensors: Sensor Boats were much stronger.

2) Explore Ships: Sensor Boats were much stronger and could scout quicker.

3) Pirates: Sensor Boats invalidated pirates. They couldn't spawn near your territory once you had sensor sight, and you could see them from so far away away that pirates were never a threat.

4) Sensors on regular ships: Sensor boats were a much more efficient use of space/cost. There was no point to putting a few sensors on regular ships.

So that to me is an exploit.

It'd probably need map-scaled sensors included as well, tbh. Once again, on the smallest maps having 1 of each type of sensor might show you 50% of the map, but on the largest maps sensor ranges of under 50 are pretty insignificant.

Once again, I can't help but think that maybe the game would've been better off not including some of the map sizes - either the very small ones or the very big ones - because there's too many things which simply don't scale properly over such enormous differences.