I actually did a simple test of the latest patch and it has issues.
Things like '<' and '>' in headers become html entities so you wind up with headers like
Message-ID: <....> To: My List <firstname.lastname@example.org>
in the delivered post which don't work well for replies.
More significantly, this will really only work for messages which are single part text/plain. For multipart messages, all part headers will be lost and all part contents will be collapsed into one part.