I would love to see a flexible config where you can add your carrier and the formula for the link. Then the tracking_URL would be formed by the system, making emails and order status a breeze to setup. I envision there being variables that can be merged just like elsewhere with Liquid.
Generically:
Carrier = MyCarrier
Link formula = www.mycarrier.com?tracking_num=[Line Item Tracking Number from Order]&some_other_data_like_destination_zip_used_for_verification=[shipping zip from order]