I think the issue is really the difference in behavior between lists
with Mail-via=DISTx and non-DIST lists, rather than the difference
between DIST1 and DIST2.  I too think that it would be a significant
improvement if LISTSERV were changed so that DISTributed lists
did their final explosion using the MAILER on the last LISTSERV
node.   In June's case, this would mean that LISTSERV at BYUADMIN
would pass just one mail file to the BYUADMIN MAILER for all "n"
STANFORD recipients, rather than "n" mail files.  This is the
same way that LISTSERV has always handled the non-local recipients
of non-DIST lists.