It would be awesome to have the ability to customize ones toolbar. Basically to be able to remove or add any command jaikoz provides within any of the drop down menus. That way one can put there most common actions and tasks in buttons right in front of them. ie drag a single edit item like Swap Columns Artist with Album, or drag a single action item like Local Correct Genres to the toolbar to create a button.
Another thing that would be really handy is the ability to create macros or custom actions and be able to save them as a button. For example, be able to tell jaikoz to select all in Comment, Genre, Not Support List, Unknown List, and then Delete. Or to do a Find and Replace on a column and then Save, etc. Something to provide an easy way to automate a users unique tasks and let them execute them at a click of a button.