EDIT: Do you have keys currently in use that don't need to have commands actually assigned to them? These commands could be just accessed from dialogue boxes from the main menu instead. That will free-up more keys for more important tasks.
I thought about removing the star/galaxy/planet toggling from keyboard (Y, U, I, O, P), because I actually use the F4 menu to toggle the objects rendering. There are many other keys that control rendering too, that do not need to be binded to those keys. Those key bindings came from a time then SpaceEngine had no GUI, and I needed it to control rendering in real-time for debugging purposes.