So what I would expect is:
- High fill factor would produce little aliasing
- Lower fill factor would show higher microcontrast but much of that would be fake
Whats your take on the issue?
That's correct. A low fill-factor will result in more of a point sampling, with detail popping in and out of focus and detail missing if it happens to fall between the sampling apertures of neighboring sensels. Jaggies and aliasing artifacts galore.
A high fill-factor will have a much better behaved roll-off to Nyquist, although with a somewhat lower MTF.
Micro-lenses will artificially increase the apparent sampling aperture size.