I've found that with scheduling tasks for the future it's important to do a final check before fulfilling the action, whether it's sending an email, push notification, etc. You don't want to send a reminder for an event that has been deleted, for example. That is why I have decided to keep the scope small and let developers make the final decision there.

Reports and retries are definitely things that I think add value though, and I have plans to expand on that.