The point about the backstage is that it should be organised logically so that there are simple rules governing it's layout.
It's more important that it is logical and consistent than that it is efficient - it is the job of themes to adapt the TiddlySpace interface to maximise efficiency for any particular task or context. We don't want it to become a dumping ground like the system tray in Windows.
For consistency, spaces and themes should not mess with the backstage. But it would be reasonable to allow users to customise it themselves.
It's more important that it is logical and consistent than that it is efficient - it is the job of themes to adapt the TiddlySpace interface to maximise efficiency for any particular task or context. We don't want it to become a dumping ground like the system tray in Windows.
For consistency, spaces and themes should not mess with the backstage. But it would be reasonable to allow users to customise it themselves.