[Humdinger]

As of right now, you can totally customize the menu and submenus, meaning adding, moving, deleting, renaming any menu option, as well as having an unlimited number of menu items.

 
I'm very much looking forward to that! I removed many of the submenus that I never use by cloning your github and editing Includes.xml. Every time I rebase your changes in master, some patches don't apply cleanly and I have to resolve conflicts manually...
When your 'skinshortcuts' branch is ready for testing, give us a shout.

Would you be willing to trade having up to six shelves as we have right now for having up to two (the two could be shown at the same time, kind of like the Jarvis shelves), but totally customizable, like the menu/submenu?  Please let me know your thoughts on this.  Thanks.

I could live with that.
The only menu where it might be a bit awkward is for 'Addons'. Here it really makes sense to have the shelves separate for the sub-categories (audio, video, programs...).
OTOH, as the shelves will be totally customizable, people are finally able to remove unneeded stuff from there and can mix addon categories to only see what they really need.

This is all very exciting. You're going from just updating Amber to work with Kodi 18.x to adding massively useful features!
Thanks, Bart!