I think that as a tool a complete user management interface seperate from Microsofts awkward and at times bloody useless server GUI would be welcome. A list of features should (or might) include:
Bulk user creation, with the option of setting up usernames with a pupil identification context such as 05Nuser for a user called New User who joined the school in 2005. Several other options could also be integrated such as teachers initials for their usernames. Users should be impoterd from primarily CSV files and optionally from Excel or Access.
Bulk Group management. This would allow admins to move, join or prune users from groups en-mass.
User Backup. Perform a backup of the LDAP users database and allow for user restoration. This could be useful for sooooo many reasons.
I have no idea which language should be used, but such a project has to be worthwhile.