It would be really useful to have a calendar feature where you could set a tentative send date for an email draft, and then also have the scheduled and sent emails show up there too.

That way you could quickly look at the email calendar to see your send schedule for the upcoming week/month, perhaps use it as a to-do list to knock off emails in the order in which they're sending, and also be able to quickly look back on emails that were sent in the past in a more visually digestible way than the "scheduled and sent" list view.

Additionally, it would be helpful to quickly see audience overlaps or gaps in messaging.