Hi Henry;
I am going to offer a different take on this than you. I agree that the image illumination will be limited by the pupil diameter. I also agree that the edge performance will be increased, but for reasons of vignetting, not stopping down the aperture or changing f numbers.
Some useful diagrams pertaining to the following at
http://electron9.phys.utk.edu/optics421/modules/m3/Stops.htm
The aperture stop of the systems sets the light cone for the system. The exit pupil is only an image of the aperture stop and remains constant. The system f number is the ratio of the aperture stop to focal length and only changes by physically changing its diameter, an iris, to change the light cone. I believe stops apply as encountered in the direction of wave front travel. Also, even if the eye generated its own entrance pupil, and then it would only be at the binoculars exit pupil image, that aperture would only apply to the eyes focal length
If the exit pupil is a constant diameter and the eye pupil is smaller, then only the central portion of the wave front, or central rays, enters the eye. This explains the light portion and also explains the decreased aberrations, the rays, or portion of the wave front, from the outer edges are falling outside the pupil diameter. The eye is not modifying the binocular optics, it is just not accepting all the information furnished to it.
In an attempt to verify some of this, and as part of my ongoing DOF experiments, I tried to see any difference in DOF with changing f-numbers and could not see any. To my eyes the DOF remains pretty constant regardless of my pupil diameter. Any changes in f-number would alter the longitudinal-lateral relationships or magnification.
For discussion at a future date concerning larger exit pupils, try this. Take a pair of 8x20s or similar and turn them around. You now have a 2.5 mm aperture, 20mm exit pupil and a 50 degree true field of view. Move your eyes from side to side and toward and away from the binos while watching the FOV and apparent brightness. Give some thought to what this means.
Anyway, an alternative opinion.