Frankly it's a totally different technology from Wii remote.
Wii remote uses IR sersor bar to do the positioning, like your leaser guiding missle.
But it uses much weaker and thicker red LED, which makes the guiding really rough.
The bottom line is Wii remote's pointing system is just not accurate enoguh for gun games on HD resolusion.
GunCon3 uses 2 makers and a CCD camera inside, basically working as reverse of eyetoy.
This means GunCon3 should have minimum,4x4 pixel accuracy which is very accurate for games.
I hope they put a simple 3D acceleration motion sensor on the lefthand stick.