Re: Why propose IMAP for Hotmail account creation, when Exchange is available and more efficient?
I'm not sure about "more efficient"... but:
We currently can only do OAUTH2 for IMAP / SMTP, not sure if Hotmail's EWS even supports that.
Also, not every user uses Hotmail's Contacts / Calendar.
Also, implications for push mail.
And also, historical. So good question, should we switch? Because of OAUTH2, we won't be able to right now.