I absolutely love the Multiple Artist Splitter function of tag editing, and use it regularly.
If I may, here are some ideas to make it even better:
1) The characters "/" and "\" not currently recognized as artist separators and do not work when "Split" is clicked.
2) A button to "Reverse / Merge" the Artist List. This will make it easier to re-combine the "Display Artist". For example, if I have the artists "Aaliyah" and "Timbaland" I'd like to be able to click a "Set Display Artist" button to set the display artist to "Aaliyah, Timbaland".
3) A "Drag-n-Drop" handle on individual artists would make it easier to reorganise the position of artists that have been split. This will work well with the aforementioned "Merge" option when we edit tracks with multiple artists.
4) When clicking the "Split" button, it should remove any possible duplicate entries that may exist in the list. I know its rare for this to be required, but does sometimes crop up. This will eliminate the need for us to manually check for duplicates.