Doesn't YAML fill the same slot, allow comments, and allow much saner human interaction? And as a bonus it's 100% (?) convertible to JSON (minus comments of course)
You'd have to add a validator to disallow some of the weirder YAML syntaxes. And once you have such a validator, you have neither JSON (it won't parse) nor YAML (it's dangerous to parse the file as YAML without running it through the validator first).