Few suggestion that we would like to highlight you w.r.t MailEnables feature:
1. Configuring an account to be a catch-all account via Web Administration.
2. Comments / Description field to be available while creating a mailbox via MMC and WebAdministration. The comment / description field must be visible only to admin via mmc and Webadministration.
3. If an email address contains underscore, i.e "_" its not displayed correctly in the field available in WebAdministration
4. Print feature in plain text editor
5. Auto Spell check when sending a mail / composing a mail. (as currently we have to manually perform spell check)