When adding/editing a publisher for a classical work, I miss the possibility to attach the catalog# for the score publication.
Very often this is easy to obtain.
This can also be used as a reference to what publication do (or did) exist, in case a work has been published in different editions.
Additionally, attaching the score editor for a specific edition would also be a great thing, where it applies. (For instance Busoni for certain J.S. Bach editions).