1) Exclusion ability to block incoming and outgoing internet access and to block eMail addresses, domains and SPAM.
2) Ability to create standards for Passwords. i.e. Forcing designated legnth and mixing of characters (caps, numbers, etc).
3) Web access statistics report. Hits per page, etc.
4) Quotas (files storage) for libraries and users.
5) Ability to nest iBays to limit the propagation of "folders" that users see.
6) Ability to assign a user to any group INCLUDING Admin (but probably not ROOT).
7) KDE, XWindows or just an Internal file/directory browser to navigate/edit & read files through the entire system (as Root) whether VIA Network Neighborhood or a free standing interface.

Ability to create aliases without having to create a user. I would like to have certain people in my company eMail forwarded to their personal, external ISP without having to add them as a user to the LAN.