If an administrator changes a user's SIP address because of marriage, divorce, etc., automatically correct that users contact in all other internal users' contact lists. This will prevent that user from appearing as "presence unknown", and they won't have to remove & re-add the user with the new address.
The resource kit for OCS provided a script that allowed administrators to add and remove contacts and groups to users (LCSAddContacts.wsf ).
Please, provide this functionality "out-of-the-box".
It would be nice if you could assign a photo for these objects to help identify them. Tom Arbuthnot wrote an article about it at http://lyncdup.com/2012/12/lync-2013-setting-a-user-picture-for-an-application-or-response-group-contact-object/.