1. Horrible and cumbersome client that doesn't conforms to basic GUI standards. Non-resizable or modal windows and dialogs, repetitive "click-fest" actions and don't get me started on rules - 1995 called and wanted its drag-and-drop back. It's 2008 now, you know, even students and open source projects on sourceforge are more user-friendly. All we get from version to version are tiny enhancements and gimmicks.
2. Archiving mail - Novell took this relatively simple task to a new levels of difficulty. Every folder in the archive has to be restored (read clicked and selected) separately. Nicely done...
2. The only mobile sync solution is dying together with its zero iPhone support.
3. Mails, documents and attachments are stored in zilion files, so backups take forever (if you manage to find a backup solution that supports Groupwise, that is). The state-of-the-art and recomended solution is dialog-bash-script product named Reload from Gwava - a company that made fortune on delivering features that Novell was unwilling, unable or refused to implement. Their whole strategy of "Let the partnes make some bucks" is appealing, but hey you didn't need those features anyway..
4. Slow and unusable DMS with intergration that supports like four file types.
5. Adminstration is possible only through an ugly java application ConsoleOne that needs direct file access to domain folder. Now that's what I call a C/S solution, very handy in situations like when you don't have a client installed and behind router/firewall.
And the list goes on. I'm sure users and IT people will all miss those features, but I won't.
If those everpresent Novell fans would leave their closets, they would see Novell fame of Netware 4.x era is over and it's Novell who's playing catch-up.