A user configurable timer that would allow Hal to do a "check for emails" and announce if any were received. (every 10, 15, 30, hourly, etc).
Yes, learn from text file the way Hal 4 & 5 did.
A mute button that worked to stop Hal's speech.
Some tutorials for those users wanting to develop their own plug-ins
(which areas to use, how to set them up, what data they can contain, etc.)
A much needed Hal 6 Help file for new users.
Wish list: An "on the fly" editor or command that would allow the user to either have Hal "Correct that" or "delete last reply" to keep mistakes from becoming part of Hal's knowledge.
Time reference since Hal and the user last chatted.
The ability for Hal to keep a secret and not have it disclosed to other users at home.
I have a lot of other ideas but they would come under the realm of plug-ins.