I was playing with this for menus in the feature__drag_and_drop branch, but decided this would be a lot of work. Some menu editor UI improvements were made and are getting merged into v11 (via the feature__hybrid_responsive branch).

We also have subcategory ordering for catalogue categories. I can't remember when this was added. I think it's probably bloat honestly, the vast majority of people will be fine with alphabetical order. So I think we should drop it.