Netware servers are not being canned, Netware 6.5 is the last version of 'traditional' netware and now most of the services that netware offered are being ported to Linux. I understand that Netware 6.5 will be supported until at least 2012.
Netware itself is becoming Open Enterprise Server which offers either a Linux or Netware kernel.
Netware is not responsible for AD directly, Novell Directory Services (NDS) which is now called edirectory was Novell's directory service offering that Netware used, edirectory can run on Netware, Windows, Linux and even some Unix flavours I believe. Microsoft realised that they too required a directory service for Windows 2000 as the NT4 domain model was rubbish.
Netware is easy to administor,all admin work is pretty much done in a web browser nowadays, its a rock solid OS, there are no known viruses for netware, you can make a netware server look like a PDC, it can host native file access for windows, macs and Linux.
Now I like Netware and Windows 2003 and find they both offer pretty much the same services and I certainly don't want a 'which one is better debate'
Why are people getting rid of them? I don't really think people are. My understanding is that most people who have Netware are either upgrading to the latest version (6.5) or moving to Linux and people who have Windows NT4 or 2000 networks are upgrading to 2003.
There is a whole lot more history to this than I can possibly type up here.
All you need in this life is ignorance and confidence; then success is sure.
- Mark Twain