JSON but with the structure of YAML, would be nearly perfect to me. JSON was not designed for humans to read and write directly, it happens to be easy enough that it's quite common but it's not exactly a nice experience. Take that base and remove the need to quote key values, enforce indentation for clear structure and to remove the need for braces and commas (the no trailing commas rule in JSON kills me too), and support the markdown-like list syntax alternative and I think really that's all most people want out of YAML anyways. I don't understand or ever want to work with their references or variables or whatever the hell they add, any of that is much better off in code than in config as far as I'm concerned.