There seems to be a logical disconnect in your message. You assert that
issuing XXXX without also enhancing Subject specification will REDUCE
available functionality.
This doesn't compute.
Subject doesn't change, so it doesn't have less functionality. Body
changes, to get vastly more functionality. How does this sum to to be
less functionality?
To the extent that you assert that you have been doing highly non-standard
stuff (no matter how justified and even desperate that action) but that
you will have to do some special work, in order to make the Body become
conformant, while retaining what was previously non-standard encoding, but
now will be standard. Well... Sounds like a great motivator for
attacking the re-definition of the headers, but strictly as a separate
project.
Dave