It would be great if all of the Watson services that have APIs (including Discovery) had a Postman collection that anyone could download and import into their Postman. If the collection took advantage of "Environment" to define variables (e.g. discovery collection id, env id, etc) and this way in collection you configure in one place but can be used on any API. Additionally, if Postman collection was categorized by folders by API function category with description of API (or link to guide) that would be very helpful. Basically an organized version of IBM Watson Postman collection that's ready to go and doesn't require too much modification.
I had seen that API Explorer is going away. If that is the case, the Postman would be next best toolset that would really help all developers.