An internal email (but safe to share) at Microsoft has explained a few improvements to the Exchange Online Kiosk license that will be rolled out over the next few months.
In short:
- Supports ActiveSync for mobile devices (but not tablets yet)
- Email upgrade from 500MB to 1GB
- Ability to add on Exchange Online Archive
You can read more here: http://www.boxfreeit.com.au/Productivity/office-365-kiosk-users-get-unlimited-email-other-upgrades.html