Um, this is definitely not my place, but might I submit that, though I
   also vaguely disagree with the /etc/mail/* structure (though for
   another reason), it is a policy decision, presumably made by the core,
   and one that should be taken up as a policy argument as opposed to a bug?

it is a policy we copied from sendmail.org.
   
   Anyway, IMHO, you should all be using Postfix instead of sendmail...
   and unless I'm mistaken, the reason for an /etc/mail was to allow all
   MTAs to store files in a uniform place under NetBSD. That makes a
   certain amount of sense, but if I have both qmail and postfix config
   files, I maybe want to have them in separate places.

actually, this is misleading.  /etc/mail is for sendmail.  /etc/qmail
is for qmail.  /etc/postfix is for postfix.  now, tell me why it isn't
/etc/sendmail?  i guess sendmail.org thinks they are better than
everyone else...

(actually, on most SVR4 systems /etc/mail is also used for more than
just sendmail.  eg, mail.rc lives there rather than /etc/ like it does
on traditional systems.)