I recently had another idea regarding this topic:
Create a predefined master page chain for each master page set.
In my head, it works something like this:
Open a dialog window, similar to the symbols editor, select existing master pages, and add them to a master page chain.
For example: one could first add a cover master page, then a blank master page, then 2 master pages of program notes and Notation explanations and then go on with the first master page (or a normal page).
This information will be inherent part of any master page set, and is either used automatically in each layout using that master page set or could be activated via the layout options menu („use master page chain“ or similar).
This will heavenly increase Layout speed for big ensembles, where currently one has to add the master page changes manually for each layout.
Thanks for your consideration and discussion .