In the latest 21.1.0420.641 build, adding a new way to import materials into an existing library is a long waited feature that finally became a reality. Thank you Microvellum. 

Another feature that would be great to see would be a way to import material pointers, with a prompt to delete the duplicates or add the non existent pointers into the database.  Just another time saver that comes to my mind as I work in the material spec groups.