Let’s see how well NixOS performs:
Multi-desktop installers ✓
You select the desktop in the installer, or select “No desktop” and configure a window manager (or whatever you want) manually.
I think it is not needed since NixOS has rollback built-in. You can revert any system config. change!
Only when you mess up the bootloader, you can’t boot the system. Not sure if a recovery partition would help here. You can boot the installer and reinstall the bootloader. Maybe we could have a recovery tool that does it with one click on a button?
Restore and sync installed applications ✓
Applications are installed by declaring a list in the system configuration, so you can copy that to a new install.
You can sync the list by having the config. in a git repository and use the same config. for multiple devices. Many users do that.
If an AppStore supports Nix and such a feature, it can be used on NixOS.
Privacy tools and dashboard
System settings are part of the desktop, not really the distro. NixOS packages desktops as-is and don’t add own tools.
It would be great if desktops would collaborate on such a feature.
Update notes framework
This is also not part of a distro. AppStores and Apps would have to support the framework individually.
Many AppStores and Apps already show update notes. An open standard would be great.
Graphical error messages
It would be very simple for a distro to build a wrapper for every graphical tool to show errors in a dialog, but terminal output is usually for developers, not for end-users.
If a message is important for a user, i think a program should show a dialog itself.
Maybe when a program crashes, a crash report tool should open. Not sure if it should report to the distro or developer.
Improved graphical app stores
NixOS don’t has a graphical app store, so here it fails in usability. You can look for packages at NixOS Search and add the names to your config.
So, NixOS is actually not so bad in context of these requirements.