In email, using reply-to, I can manually redirect a discussion away from
inappropriate recipients. What's the difference?
My proposal---using Reply-To to control replies, and a followup field to
control followups---is a _labelled_ change from RFC 822 semantics.
Your proposal---using From to control replies, and Reply-To to control
followups---is an _unlabelled_ change from RFC 822 semantics.
You keep complaining that MUAs don't use From and Reply-To the way you
suggest. That's because they're following RFC 822, section 4.4.4.
Of course, this is only a guess at what your proposal means, since you
consistently refuse to say what you want real MUAs to do with their two
built-in response functions.
Let your users manage their own mailing lists. http://pobox.com/~djb/qmail.html