My immediate thought. Except not "vanilla" YAML, but a safer stricter subset (iirc some people published a spec about it): no implicit conversion, no norway problem, etc. If only this gained actual traction.

The JSON in the article is a bit, let's say, heavy on the different objects and does not try to represent anything useful with most keys. All the things like `greaterOf`, `sum`, etc are much better expressed as keys than `{"children": [{"type": "greaterOf", ...}]}`.

Basically something that feels an reads like "freeform" yaml, yet that has an actual spec.