Another alternate suggestion and discussion.
10) Mail servers which use the subject line need to be supported
Add a parameter "subject" to the message/external-body.
While I don't have any serious problems with this, such servers are,
IMHO, to be discouraged, rather than pandered to. I think we have some
proof-by-interoperability testing that they are not a real good idea,
however quick they are to implement.
(1) Use of subject lines is subject (sic) to all of the little
vunerabilities that "get" header lines as they pass through the extended
mail internet. The point at which one resorts to mail servers, rather
than, e.g., FTP, often occurs when one is well off the IP-connected
network, and this is where we should seek maximum interoperability.
(2) If we ever standardize mail server functions, I'd predict with some
confidence that this use of subject lines won't be supported. If for no
other reason, there is the "one message, one command" issue, which makes
this a waste.
So, if something has to be done, I'd like to try to view it as a pre-
deprecated transitional facility, rather than something that will be
used by people in the future to argue that MIME specifies that these
things are a good idea and an encouraged implementation.
john