Thanks Joseph Chow for checking in on Stanford hosting a mailing list (discussion via email).
My response:
Right now it looks like most want something that is more accessible on the web, and further splitting discussion doesn’t seem helpful, so proposing to keep building on EthMagicians.
Threading (which Gitter among other chats doesn’t do) is my personal must have.
Jamie is working on configuring Discourse so that reply-to works as well. Or will shout for help at me 
Then we can do a trial run with a topic / group in Discourse on EthMagicians that is members-only write, world read, and anyone can join. Basically means we can ban bad actors or those that are off topic, but by default has no barriers to entry.
I personally don’t really want a Stanford domain hosting this, and definitely don’t want Google hosting it, but would also be fine with mailman (or other tools). Once setup, any particular solution is not that hard to self host.