As a designer and a developer I find there's an area where design apps could really learn something from code editors. There's a trend in recent code editors to use a Command Pallet (⇧⌘P) which allows you to type anything and find/invoke anything. It's great for quickly getting to hidden things. For me, Affinity apps packed with a power and you have to hide some of those options (if not most) to make the user interface, well... usable. A Command Palette could really help users to find and use different aspect of apps without having to dig around the user interface.
Some example use cases:
find and open any palettes
show/hide studio panels
run macros
open a specific preference
run commands that don't have keyboard shortcuts
Take a look at how code editors (like VS Code, Atom, Sublime Text) are using them to get some ideas.