It's not that simple. A 'bigger hole' would mean an aperture of f/1.4 or similar. This in turn would not just change the amount of light, but a slew of other things - like softer images, shallower DOF, getting washed out more easily in daylight (remember, the aperture is not variable). Any imaging system is a heap of compromises. Singling out just one parameter will not necessarily improve the performance of the imaging system as a whole.