Here is an idea I think would be useful. In Engrave mode, when making changes to a Master Page set, it would be handy to be able to type “F”, “S”, and “N” to toggle the switches for “Frames”, “Staff Spacing”, and “Note Spacing”. I find a lot of mousing around is necessary to turn the switch on, do the edit, turn a different switch on, make the edit, etc. Perhaps while in this mode other shortcuts could trigger actions such as “Insert Music Frame”, “Insert Text Frame”, “Insert Graphics Frame”, etc.
Obviously, this is a low priority in the scope of things, but the beauty of this forum is that we have a place for people to make suggestions and be heard out by not only the users but crucially, the development team. “GO TEAM”! 
I am personally against most single-key shortcuts, as I think they are too easily invoked, but some sort of keyboard shortcuts to toggle those switches would be very helpful.
I learned here from Daniel himself that you can already create your own shortcuts for staff spacing and note spacing (I chose alt-cmd 3 and 4), which is very convenient. Not sure about Frame, though.
Ok. I just checked, and Edit Frame is also available in the keyboard shortcut editor ! So I changed my keystrokes to alt-cmd 3, 4 and 5 for Frames, Staff spacing and Note Spacing — alt-cmd 1 and 2 being the shortcuts in Write mode for Page or Galley view (defaults).
Hope it helps !
You can find these commands in the Edit category (not the ones shown in the Engrave category) in the Key Commands page of Preferences.
This is just fantastic! I didn’t know there was the possibility to set up shortcuts for turning toggles on and off. I set up my own key commands for these 3 editing modes as well. I love it!