OMG I know, the wiimote's tracking was done by going off the positions of the camera servos, which point themselves at the light bar. So it's got built in lag, and, the positioning is all based on distance from the light bar, so the size of your TV is irrelevant. Obviously that means you couldn't actually "Aim", instead you basically moved until the crosshair was in the right place. Takes all the fun out of light gun games...
Now, I know the nintendo zapper was pretty primative, but still, it felt accurate and responsive. All it was doing was using a sensor behind a shroud so you have to be pointed at pretty much the right place for the gun to pick up the white boxes when the screen flashed when you pulled the trigger. Why can't that work on modern TVs?
Failing that, the sensor bar can work, but your light gun needs a pretty wide fov to allow you to calibrate it to your TV, which nobody ever does for some reason...
I feel like the Wii may have killed light guns because people figured it was close enough but nobody really liked it.