Could there be an option like "Workspace: Quick tagging mode" to be switched on under Preferences that does the following:
When activated, after editing one tag in workspace you only need to press the Tab button to jump to the next editable tag with focus and cursor on the input line.
My second wish would be an empty field, when the tag contains nothing. Today there is always a "-" which must be deleted before filling in the tag...
After that you could easily go through your workspace and tag a file from beginning to the end with a minimum of input. ;D