Subject: GUI for installing compartmentalized apps?
Is this something planned for Spectrum down the line?
Yes, but it might be a while. I have some ideas for how it could work -- a Nix configuration file could be supplemented by an imported JSON (or similar) file managed by a graphical tool. This would mean that, even when it wasn't up to some complex task like a package override, a graphical tool could be used for managing the simple cases.
Such a tool would also be immediately useful for NixOS, so even non-Spectrum users could benefit from it. It might even mean somebody not even involved in Spectrum might develop it!