Wariag. It's good to read your post. It is something many have been saying for years. Many of my friends and I have tested this with a few lenses and found the same particularly with FF 35mm sensors.
It is a very controversial point especially for those who own FF sensor cameras. But the point is very well documented.
However we have also found a fairly consistent improvement with many good lenses on crop DSLR vs their performance on film.
The absence of any of the lenses shortcomings in edge performance is an obvious answer to some of these improvements but noticeable improvement in centre sharpness in real world photography (Different colour shades and resolution of colour etc rather than back line resolution charts) is often observed.
Don