You are talking about Debian holding back random packages for stability. This is of course not very cool but it needs to be tested.

I am very much in favor of isolate app environments controlled by upstream devs, containerized and with a permission system. The system is made by the distro, and can be stable and very tested, and the apps are simply isolated and made by upstream.

There is no xscreensaver on Wayland and I think this will not come back?