I understand that design decisions are often like looking into a crystal ball. But the removal of 64px icons is way too early in my opinion. I am acting as a sysop in an university and migrated hundreds of machines from KDE (or even worse Mac/Win) to (GNU/Linux) with Gnome while the last 3 years.
4k displays are definitely not the default size at the moment.
I bet this change will not go over well as soon as Gnome 43 has arrived in our GNU/Linux distribution. No offense but this would feel like a classical design decision made by MS.
Extended support for 64px icons for the next 5 years would be a smart and strategic decision in my opinion.
Don’t get me wrong, I thank all the developers for so many other very good things in Gnome! 