For starters, being able to automatically set a Label Printer as your default printer on the mobile app would be useful, like on the desktop.
Multiple Package shipments on the Mobile app would be useful.
And, having a rate calculator option within the shipment, much like the desktop, would be very useful. I use all of these things a lot on the desktop and I am trying to get our company to move into the Mobile app to help with the speed of packing, pulling and shipping orders.