Would like to see integration of shipping with UPS, USPS, etc to allow for label printing for orders that require shipping.
If you decided to implement this, Is there no way you could just create a way of connecting to couriers via an API. Many have apis for online stores. Excuse my ignorance of tech issues. But if such a thing is possible you could just have a standard interface regardless of the courier service. I'm pretty sure UPS has an api, but i'm not technical so i dont know if that could work with your software. This would be great for enabling your software to be internationally used.
I currently use an api from my courier company with my wordpress online store and cashfootprint for the physical store and stock management. If this was possible i would just connect to my courier via cash footprint instead. Much more stable and reliable.