Add an option to disable reading tags, so that file loading for a large number of files be very quick. Give an option to read only when clicking in the left editing box, or ctrl clicking or something like that. That way it doesnt read every file selected. (It's a pain to wait when i press Ctrl+A [select all...])
And let mp3tag double as a batch renaming program... Give an option to view all files from a certain folder. It would be great to rename quickly like mp3tag... put an extra button to disable the tag reading and use filename-->filename to rename!