I had been led to believe that one of Wayland’s strength was solving the correct window coordinates save-and-restore problem. Does someone know what happened here?
It’s literally the opposite. Windows aren’t allowed to position themselves on Wayland (because it’s unsafe or something). Window state save restoration must implemented by the compositor itself. Not sure about GNOME, but KDE doesn’t have that.
Sure, it’s hard to craft a perfect solution. However the status quo for a long time was that applications were doing it themselves. And Wayland took it away without providing a replacement.