Ability to generate simple reports like https://repeating-export-for-ynab.com/ (which exports a csv of all recurring transactions). This could be useful for getting an at-a-glance picture of all recurring bills.
Update:
Refining this because I think we riffed on a pretty good idea in Discord here. Basically, it'd be slick to be able to view a "timeline" of your recurring/scheduled transactions, past, present (today) and future. Depending on how complex this is, we might even be able to tack on notifications for upcoming transactions, something YNAB does not support.