Just a thought … to be able to view and possibly edit the nav slug from the page info tab.
Similar to how you are now allowing a user to create a nav slug for a new page during the creation process it would save a lot of steps trying to look up a nav slug or edit a nav slug. Currently, when I remember I put the nav slug in the description but I often forget.
Also this would easily surface any page that doesn’t have a nav slug assigned.