I didn't tell that we are ready to switch today. I certanly agree that
it's a system administarator who should make decision.
But IMHO,
1) absence of maildir support in a M[UT]A is a wishlist-priority bug,
and in some day its priority will grow;
2) it's would be very nice if sysadmin change configuration in _ONE_
place (not if every MUA's conffile and/or every shell's environment)
to switch his system to maildirs.
-- Ilya