This was previously discussed in great depth. Personally i see no problem with diminishing returns. Note it is not terribly unbalanced as the AI will use your sensor boat designs in future games unless you delete them (several precluding factors not withstanding). I stopped using them a long time ago but truth be told i modded starbase sensor range a bit
Yeah I am not worried that it is unbalancing because everyone can do it. I just think its moronic. I would like to see one of the developers that is "winning the argument" with Brad come here and defend the idea that you should be able to build ridiculous sensor boats and run your fleets with no scout or sensors on any ships.
And why do I need to put sensors on a ship anyway? There is a lot more space on a planet since one tile easily has about 5 million times the space of a single cargo ship, so I should be able to plant enough sensors on my homeworld to see out to 5,000,000 hexes. This should cover both my insane map and any other maps that are being played in other people's games at the same time.
I want to point out that physically, diminishing returns is a certainty with this type of equipment similiar to the inverse square law of gravity. Granted, the gal civ 3 universe is effectively 2d, but the same principle applies.
For example, lets say for simplicity you only have visibility of the hex you are in prior to installing a sensor array. Lets say your first sensor array lets you see out to all the adjacent hexes, which is 6 new hexes. Now in order to extend your range out one more hex, your sensor will see an additional 12 hexes, so logically it should take twice the power. In other words, one sensor array for one additional hex diameter, and 2 sensors arrays to extend it out one more hex.
Of course, physics should be the handmaiden of play-ability in games. Precisely my point then, since I think the game is improved with the addition of diminishing returns, so I argue that diminishing returns is not only more realistic, but also more fun for the player since he now has to include sensor ships in his fleets or he will be blind as a bat, which conforms more to player expectations for how a galactic empire building game should work. Q.E.D.