It would be helpful to be able to import web pages for citation purposes into Papers. You could do this in Papers3 and it would actually display the web page when you clicked on that citation. Very often I cite web pages, technical pages or programs from governments or industry and it would be useful to be able to easily import/store/cite these types of materials.
It would also be helpful to link citations to worldcat, amazon, google google books, etc for importation purposes. For citing books.