Member based mailing list
Mailing lists - we have a mailing list where members (and non-members) can receive and send messages. There is nothing similar in wild apricot.
We use forums functionality instead for this and we do not have plans to introduce special mailing list. But we do have listserv feature requests – this may be similar to what you want.
Yes! Our association greatly needs this, too. We have membership levels but also topic-based learning communities. Our members simply haven't used the forums, so we're paying for an API to create separate listservs that allow members to message all the others in their learning community. Greatly appreciate you considering this addition.