I just got my phone on Friday and am starting to experience some of the quirks of the exchange implementation. To a great extent it's working great and with exchange 2010 to confirm that question!

Here's my input for consideration (If not covered in previous responses):
- Better exchange calendar integration i.e. I receive a meeting request, I can accept it and it subsequently add's it to my calendar (device and exchange) and sends a response to the meeting organizer.
- Unread email count on mailbox screen (maybe a counter next to the title)
- Fewer steps to get to inbox. E.g. launch email>selecmailbox>go directly to inbox and skip folders. The palm pre does this very well and it's quite useful
- Autoload of images
- Different color for priority mail (e.g. make the email red in the inbox)

Other items such as GAL search have been covered so no need to mention here.

Thanks for reaching out for feedback, it's the best way to make sure you invest your time in the right feature set for end users.

Cheers.