Maybe I'm missing something, but most of your comments seem to be focused on limitations of the sensor, not on the lens itself. (It's hard for me to picture how a lens would behave differently at low light intensity than at high intensity: the light rays all bend the same way regardless, right?) Your point about diffraction-limited resolution is well taken, but for two lenses with the same aperture projecting onto identical sensors it sounds like this technique could make low-end products more competitive with high-end ones. (Let me know if I've missed your point.)