Regardless of the reasoning laid out in the OP, it's difficult to argue in YAML's favor comparing it with JSON. I'm not an ardent fan of JSON either -- both YAML and JSON have issues wrt inconsistencies:

- what draft of JSON Schema are you using 4? 7? Neither?

- what version of Swagger or OpenAPI are you using?

- etc.

Sure, it's great to see ongoing development of schemas, but with each new development we have yet another dialect to consider/support.

In my view, perhaps an even greater problem with structured data formats in general is the void that separates them from programming languages esp. static languages such as Java where static type information is otherwise leveraged. The industry standard solution, code generation, is awful in almost every respect. The Manifold framework looks promising in this regard (http://manifold.systems/).