It does feel like people may be overestimating the impact of it, especially on larger fleets. Probably a consequence of the "actual sensor range is something like a log scale of the strength/profile", which isn't explained very well. Need to explain this better somewhere, I think. Perhaps right on the civ-grade hullmod's tooltip. Hmm. Just not sure about how to phrase it so that it's sufficiently clear and doesn't "break character" too much.
Mhh...maaaybe it would not be a bad idea to hide the whole sensor profile/strenght thing completely and always refer to sensor/detection range. Even if players understand the mechanic (and that's a big if), converting between these two, and be it just as a rule of thumb estimate, is just not something players want or realistically can do.
Instead of saying "this thing doubles sensor profile" how about saying something like "this thing increases detection range, a lot in small fleets and a little in big fleets". With nicer words. I think that would help clear things up. (To be honest, that is how precise I do the conversion in my head at the moment. So, not precise at all, but its serviceable.)
Then the sensor/detection range tooltip could list how much the sensor/detection range of the fleet would decrease/increase if a specific ship would be removed from the fleet. That's tangible, practical information.
Since I'm already typing, two more things for the tooltip: It would be useful if
a) besides the medium sized fleet (maybe use a patrol as example?) also the detection range for a typical small fleet (for early pirate hunting) and big fleet (trade convoy) would be mentioned. Besides being "good to know" that would drive home the point that this is a variable, dependent value.
And b) if this range could be visualized (when hovering over it?) with a circle or somesuch. The "2000 units = 1 map grid" doesn't really cut it.