Here are a couple of suggestions for User Administration:

+ Be able to filter for "Never" in last access, etc.
+ Be able to change the columns shown in the user accounts list, such as being able to add columns (like one would when viewing files in Details view in Windows)
+ Be able to filter for those not assigned to any role in Moodle
+ Be able to filter for duplicate fields (such as users with the same last name) to help find duplicate users

Thanks,
Kyle