I'm with this above statement, the opening on my cover for my camera is freaking huge compared to the small dot that is really the Camera lens...
The opening on your camera could be larger than others. If you go to the developers site for apple you can obtain documentation should you want to create covers for the iPhone4. In there it explains about the amount of relief you must have around the camera aperture to prevent distortion of the image being taken.
Larger lens could possibly = optical zoom of 2x? maybe??
-Or possibly an extra LED for macro photos???
*just saying those could be some neat little features, we will just have to wait and see