Change the PIN system to be a REAL single PIN, shared between Lync and Exchange, like the Active Directory Account Password
MAC Address to Lync User Mapping for Zero Touch Initial Setup. This could streamline initial voice implementations.
I think it would be useful to receive an automated IM/email when the PIN expiration time is approaching (e.g. 30/14/1 days in advance). Inspiration for this idea was: http://blog.orbitone.com/post/Never-be-late-for-an-online-meeting-again-CEBP