It doesn't matter at all what kind of promise flavor an API returns because promise implementations treat other implementations as interchangeable.

Even the ES6 Promises implementation supports this:

    Promise.all([{
        then: function(r) {
            r(3);
        }
    }]).then(function(result) {
        console.log(result);
    });

Here the plain object with then could have been any promise implementation, even jQuery, and it still works.

For good or ill, it's not going to happen. ES6 is meant to have a VERY small promises API (although you can use a library like Bluebird as a wrapper around the native implementation to provide a better API). A more full features promises API will be coming in ES7.

See, for example, the discussion about adding a .any() method to the ES6 promise spec: https://esdiscuss.org/topic/promise-any

The conclusion basically that yes it would be useful, but it'll have to be ES7 not ES6.