Great idea for putting the rewards helpline number directly on the app. Just updated my iphone app, it'll definiely save me time as there have been a few times I've had to call in and work through the phone tree - minor annoyance - to reschedule stays as sometimes work schedules change last minute.
Id like to suggest another tweak to the iPhone app - being able to search locations on the map and filter by hotel category number!
If anyone has any other cool ideas Id love to hear em! (Maybe Marriotts watching?)