Idea: Extend the options at the respond-tab. Enable saving several different responses, since that is the reality: a response with the happy flow content, a response with only empty result, an error-response, etc. and store each of them. This can also get derived from the Swagger.json.
Mainly: keep developing this "Consumed_REST_service", see the other ideas 4779, 5092 and 5245
If you have not used "Consumed_REST_service", and still use the "Call REST", you are missing out. "Consumed_REST_service" is awesome! One of the big improvements that Mendix has delivered in the last few years.
It gives you (almost) total control design-time, when you are busy creating the consuming microflow of a published service. Instant creation based on a swagger definition. Instant designtime testing.