Sure, but you also can't balance it against the smaller setting when other players might never touch those. It's another case (like LEP) where the map size ought to be taken into account - ship range is already modified by map size, sensor radius should be too.
you're right, and surely a tiny galaxy also qualifies as a "most extreme setting" as well. the best way to start is to look at how things play out on medium settings. however, the differences from medium/large to insane/tiny are so extreme that it really would be best to not include a static hardcap/modifier but to put this into relation to the actual galaxy size.
True if you play on small maps you suddenly can see the whole galaxy. The ai in the last 3 games is now using my sensor ship designs which I found amusing.
I have yet to see a proof that shows that the AI is even using these ships in a somewhat efficient manner, especially on harder settings (which is chosen by players to get a challenge from the game). There, the AI virtually has no FOW, and IIRC he gets bonuses to sensors which enables him to see alot of stuff already with his normal ships/planets/starbases.
The AI also knows the location of every resource by default, the game globally shares information of ships/fleets etc pp.... the only thing he practically has to do is to send a scoutship to a planet to make this planet known to him, afterwards send the colonyship. I do actually believe that it is better for him if these scoutships are designed to be cheap (or fast), because, with the difficulty bonuses these ships already do the job satisfyingly well and then, cranking out more cheap normal scouts out which can go into different directions is probably better than these expensive cargosensorboats. Especially early on when planetary production is still low, time matters (everything that can be dispensed into producing colonyships could decide whether that colony ship reaches the planet as #1) and where pirates are around which continuously shoot down unarmed AI ships (and here, multiple cheap scouts have a better chance to do the job done, or in other words, the loss of some of them won't matter as much as if an expensive cargosensorboat is shoot down)
So in my opinion these cargosensorboats only give the player a really strong bonus, and they could even weaken the AI game in that the AI is spending production & time on something from which he doesn't really benefit from... 
