Access to statistics, Domain/sub-domain management, Email management (if email is provided), ftp management, disk space/bandwidth usage monitor, control over bandwidth throttling to control individual bandwidth usage (if limited to a pre-determined amount per month and to limit bandwidth provided to particular usernames/groups when accessing site via ftp), control over directories (chmod/chown access via gui).
I know that some of these suggestions are unrealistic due to system security concerns, but would be interesting to have.