If all ships used thrusters only, you'd see them coming and you'd be able to intercept. But with Warp capability, I could pop up well beyond your ships, close to a planet and have my forces on the ground before you could reach me. This ability would get better and more precise as the game and tech progressed.
You make a good point. Although even at warp speed (or even warp 9 in Star Trek), it would still take quite a bit of time to cross vast interstellar distances, since i think warp 9 is considered 81c (81 times speed of light). But in order to alleviate surprise attacks, somewhere in the tech tree along the defensive path, they could have an Anti-Warp Bubble (or Dampening Field), that could be setup in a Solar System boundary (not the sphere of influence, that is too big), which would make ships slow down to 1 base speed.
The 'eyes of the universe' deal ruins the game for me. No surprises.
I agree, and AI often does not go for Sensor techs very quickly, so the never get this themselves. I think Stardock should keep Eyes of Universe, but massively scale it down and make it a 5-7 Pc Bonus (and you don't get to see every ship on the map).
As far as I mentioned bringing in some aspects similar to Civ III, I in no way meant that if you cross someones terriroty and the other civ complains, it throws out all your units to the border, that was about as lame as anything could be. But since space is so vast, sensors should work based on a range scale, so huge hulled ships with 3 warp drives loads of quantum torpedoes will pop up at a ship's max sensor range, but say a tiny-hulled scout with no weapons and low signature would only be seen at half the sensor range, giving them a greater use to attempt to monitor enemy activites, and sneak through boundaries (looking for clear space for a larger fleet).
Also to liven up the nothingness of space, and create a way to make chokepoints, and defensible positions, they should think about actually adding some of the other stuff into the game that actually exists in the universe. Since an immense galaxy probably actually would be a whole galaxy, no reason some planetary nebula's or a black hole cant be floating around. Sensors dont work in nebula and speed is halved, or whatever, the things that could be done are almost limitless.
Tom