<<How about because you can detect the compression of gas in front of a ship in warp transit?
This is the only counter-measure developed for the Picard maneuver, since sub-space sensors to detect superluminal motion are ineffective. The only other option is to claim that the Picard maneuver relies on totally disabling the target ship, and because current ships are armored better and phasor power is reduced when firing through a warp bubble, that the maneuver isn't that effective anymore. But that argument is weak>>
Wrong again. They actually explain it in one episode. The reason why they were able to use it on the ferengi is because they had light based sensors. They could only "see" outwards as fast as light basically. They said something about new ships having subspace based sensors that go faster than light, and are able to detect things at warp/light years away etc, so you'd be able to tell where the ship really was.
I feel all dirty now... yech, get it off me.