Having UPS Quantum View Notify functionality would be amazing. It's an extremely powerful tool that basically allows to send notifications to the customer regarding their delivery status, like delays in transit or if it's sitting at a UPS Access Point.
I'm not sure what other carriers have in regards to this, but I'm sure they may have something similar.
Delivery confirmation is one thing, and already very good, but having even more notifications like listed above would be incredible. We have customers who's packages end up sitting at UPS Access Points until they are returned to sender because they don't know how to check their tracking information or forgot about their order.
Let's get 10,000 votes on this. It's the only thing left to make Shipstation perfection.