I work at a pharma company which recently roled out 2000 workstations for everyone. We use exchage, outlook, and soon Active Directory. I was going to suggest that this would drive down profits. I would think that such a feature would be added after 1.0. If you really want to see the exchange protocol include then write Microsoft to release the documentation or start a petition or implement it yourself.
Balsa really rocks and just another e-mail client is redundant.
It's such a waste of creative programmers' time. Besides, evolution is more than an e-mail client. It's a groupware suite. Just remember Vector Linux that targeted to small comuters. I guess each solution should find own consumer.