I’d like to see a page that gathers all of the tags used to sort templates/TV’s/chunks/etc.
This could be useful for a couple purposes. As your site grows, you might reorganize certain tags by renaming them to something that’s more suitable, or get rid of an obsolete one altogether. In 0.9.6.x (and versions before it, such as 0.9.5.x), every tag you’ve used stays in MODx’s "memory", cluttering the drop-down that holds all of the tags.
So having a page that could edit or delete tags would solve some of these issues. Obviously, deleting a tag would come up with a "Warning: These ______ still used ____ tag(s).", much like when a Template Variable is deleted.
I haven’t kept up with 0.9.7.x development, so I apologize if this is already present in that build.
If you can’t wait and have access to a MySQL manager like phpMyAdmin you can delete the unused categories in the "modx_categories" table.