Hi ... I am starting to work with your plugin and would like to recommend a feature for you. Feature: have the ability to choose what User Roles have the ability to add posts to a newsletter. Currently, anyone with Contributor capabilities or higher have this ability. For my site, I don't want Contributors or Authors to create newsletters and begin spamming my visitors. I would like to restrict this to Editors and Administrators, if possible.
Anyway ... just a suggestion.