I think with the existing Visibility settings we already have “folders” in the Mixer view. Group Tracks appear in their own Folder, same for FX channels, and, those can also be moved. Other tracks can also be grouped into logical patterns and sent to Sub-Groups. So, I like the idea of folders for the Mixer, but, I think the existing visibility controls already give me much, if not all, of the benefits that this would allow.
What I’d really like to be able to do is move tracks around on the Mixer and have them be re-arranged on the Project main window. Cheers.