It would help minimize the number of calls per customer order if the '/shipments/getrates' API method supported accepting multiple carrier codes (for example, as a comma-separated list), or even a special value to return all carriers (for example, '*'). I am building an application that is attempting to find the minimum shipping cost, and if you want to find all FedEx, UPS, and USPS options for each order, it requires 3 API calls.
Building the API in a smart way like this makes it feasible for a script to engage in shipping optimization
