Create 'QuickTag' Groups and/or be able to select multiple tags at once
When you want to add multiple tags to a file or files, right now you have to individually select each tag and apply it to the file. I think what could be more efficient is to create 'QuickTag' groups that would allow you to apply every tag in the group to a file or files. This could make it much easier to apply commonly used tags. Another approach would be just to add a function to the current 'Tag Group Operations' menu to apply all the tags in that Tag Group to the file or files. Alternatively, you could accomplish the same thing by being able to select multiple, individual tags at once in the Tag Groups and then apply all of them simultaneously to the file or files.