Don't quote me, but I think ultra sharpness is overrated... Ultra sharp lenses have a single plane of ultra sharpness that usually does not match the less optimal planes of focus and more difficult to blend...

Often, diffraction is your friend as it evens and smooths focus of different focus planes for a better overall effect...

An "acid test" for sharpness vs diffraction would be photographing a bare tree, as super thin branches would resolve too small for the eye to resolve on a print with super sharpness, but slight blur of diffraction would make it more visible... And overall focus would be more even... High resolution also starts to reveal what I call "the dirty layer" which is dirt/soot on things like white marble that can make it dingy looking...

Photographing a lens test chart or even a sheet of fine newsprint at different aperture settings some night should answer a lot of questions about diffraction... (But this is just one plane of focus, how do the other planes blend???) Overall look is important...

Steve K