Justification: it's somewhat broken; Microsoft are deprecating MAPI and we just
don't have the manpower to get this right.

The right answer (if I understand correctly) is to have a nice official
installer for Windows that ships with something like msmtp (and which helps you
to set it up).

So we are waiting for the installer, see superseder

1. There are different flavors of MAPI and only "Simple MAPI" was 
deprecated.

2. Not all Windows users have access to an SMTP server. In particular, 
if they use Outlook+Exchange then it is highly likely that either the 
SMTP support is disabled and/or the SMTP ports blocked and/or the user 
doesn't know the SMTP settings that work.

When I have time, I will install Outlook 2010 RTM and test out darcs 
send with it. When I tried Outlook 2010 beta, for some reason it didn't 
work, but it seemed like the failure was inside Outlook, not in the 
darcs-Outlook integration.

Thanks for the input, Brian.  You may be interested in issue921 as well.

[Salvatore, does this change things?]

This is not likely nor required to be done for 2.5.