Actually, you can have the "save only some things and not others" already, by turning on: Preferences / Launching Opus / Default Lister / Ignore toolbars of Default Lister.
(Or maybe I have it backwards and you want to turn that off rather than on. Not sure.)
If that is on, the toolbars in the Default Lister will only be updated when you explicitly say so, using the menu item in my reply here: Default lister toolbars in DO11.