It would be nice to have a step type or something similar that can be added/inserted with the purpose of calling an external service for its response.
An example of this would be calling a hosted test service that provides a set of customer details which you can then use in the test to avoid hardcoding values and allowing the test to be more dynamic and thus more maintainable.
Another example that comes from my usage in calling out to a hosted test service that has helper functions for the tests, things like GenerateRandomString, GenerateRandomAddress, etc. these can be done via a JS validation but with no centralised storage of JS code we have them hosted external to LoadNinja and call out to it during a test.