In the Email Management workspace, it would be nice to have:

1. The ability to reply to an email in-line.  Right now it seems the best way to reply to an email is to have to click on the record ID and then click on the email address, vs. 1 click in outlook itself.
2. The ability to flag/prioritize and sort (as one does in Outlook).

If these tools are implemented, I could see people moving out of Outlook a bit mroe.