In Community> Settings> in the left sidebar add a "Send" Newsletter tab.
Much like creating a post (Text/images/links) allow us to send timely newsletters to everyone in our communities. If possible a template using email builder could be selected or a default newsletter template using the Community branding elements.
The community users emails are pre segmented as recipients of the newsletter, (it might be good to have an option to toggle off/on newsletter in their profile UI).
Much like the planned social planner allow us to schedule newsletters ahead of time.
It might even make sense for all this to happen in the social planner.