Rotoscoping is an enormous, time consuming task. Harmy’s work is so well regarded largely because of all the time and energy he has spent rotoscoping a number of the despecialized shots.
What you’re suggesting is rotoscoping the elements of the entire film, including elements that were not changed. Compared to Harmy’s work, that is more on the scale of producing “A Scanner Darkly” or any pre-CAPS animated Disney Blu-ray. I don’t think I understand what the benefits you’re suggesting are, but I think you are probably incorrect about them. It would be the most work ever put into a fan restoration project, and would not have a particular purpose as far as I can tell (but I am no expert). Furthermore, we would undoubtedly introduce changes in reconstructing all these layers, just as Disney does to every animation they re-rotoscope.