January 29, 2019
New Tags are created (and removed) dynamically - by Media item. Be nice to be able to change a tag name globally by right-click -> Rename on the tag in the filters list (while in Media). It would replicate that tag name change to all Media items with that tag assigned.
February 1, 2019
Thanks for the suggestion. A solution in the meantime is to toggle to the table media view and check all items with a tag and use the bulk add and remove buttons at the bottom to add the new tag, then remove the old.