I’d love to see a tool in Litmus focused on aiding content writers in writing e-mails. Something like the Hemingway App, but that also includes suggestions related to paragraph length, button text length, and spam words to avoid in the subject line, body, preview text, et cetera.

Similarly, I’d like to see the subject line tool somewhere “out front”, ideally as part of this tool, where content writers can leverage it as they put together their content and can be made aware, in the early stages, that their subject line is too long or their preview text is too short.

For anyone not already aware of the Hemingway App, I would recommend checking it out: http://www.hemingwayapp.com/