Presently through the roster versioning/publishing popup users can see all previous published/unpublished versions of the roster as well as who created the version and when. It also highlights visually what has changed between the versions.
It would be good however to be able to run a report from version A to B to list out what the individual changes made were and by whom. Users should be able to specify which versions to run the report between such as the current and previous version or any other version.