Concept is some users can only create Drafts, and then effectively submit them to some higher authority (presumably creates an Activity to notify right people) who has to Review and Schedule the mailing.
Anyone done anything like this yet?
If not, then I guess the bare minimum is a new Permission for 'Create Draft Mailing' which removes the 'Submit' option from the work flow.
Second step would be how to ensure the higher authority gets notified there is a Draft they need to review.