Meh...
"'Reply-To' Munging Considered Harmful" is twelve years old, and I don't think the list of mail clients containing "reply to list" includes any of my favorites - much less making it the default, as it should be, since at least on the mailing list I manage, it's an extremely niche case to want to reply to someone privately.
And if you do so, you run the risk of the recipient not noticing the To header and thus getting confused about whether the message was private or not - especially in the many modern clients that use a linear rather than hierarchal view of threads, where you'd end up with a "conversation" randomly interspersing private and public parts. Much better to just compose a separate email.
> Unfortunately, "reply to list" implementations are still not kind to non-subscribers. The feature assumes the subscribe-only style of mailing list. (What is needed is a list header by which the re-mailing robot can tag the message as being from a non-subscriber, so the mail client can know to keep that person in the loop.)
Allowing non-subscriber threads using "reply to all" is a fundamentally limiting feature, though.
- The most important point: if you're not CCed by someone else, you have to start a new thread; if you are browsing archives, you can't just 'forge' a reply to a message you didn't receive, or at least I haven't used a client that lets you do this. And you should be browsing archives, because the alternative is asking questions without knowing if 10 people have asked the same thing recently. If you are CCed, you only get replies strictly hierarchally located under yours; you can't really join the discussion as a whole.
A better system would allow you to join a thread at any point and start to receive followups sent anywhere in that thread (but only that thread).
- In lieu of such a header currently, or in case of clients which don't support it, if someone does reply to the list, you will silently be cut out of the loop.
- There's no way to stop receiving reply-alls. Not the end of the world, since even Gmail lets you mute conversations, but it's more clunky than necessary.
In my ideal system, all mail would be forwarded through the robot so you're cut out of the loop iff you want to be.
- Not as "fundamental", but there's no guarantee the list in question even has a usable archive browsing interface. (I don't pay enough attention to which interface I'm using to name names, but there seems to be a common archiving UI which does not wrap messages - of course they should be sent wrapped, but in practice I've often seen one-line-per-paragraph messages.)
For the record, my ideal system is somewhat approximated by Discourse, which is a forum, but gives you the option to receive all messages as email and reply via email. However, there are various implementation defects which make me not really want to promote it.