Backup credits
Add ability to mark creators on a book as "backup" or something similar for crediting creators who worked on backup stories on an issue. As it stands now, you have to mark them as Writer or Artist, making the credits page confusing as there could be many writers listed when there was only one writer for the main story.
It seems like it would probably be unwieldy to add "backup" versions of all the creator credits, so maybe a checkbox or text box next to a credit that allows the creator to be marked as a backup creator (if checkbox) or maybe the story title itself (if textbox).
We now have a Story breakdown system permitting backups.