We already have TOML and it's great. I can seamlessly upgrade from ini to toml.
[0]: https://github.com/soml-lang/soml/blob/main/comparison.md
I think where TOML shines is when your configuration schema is relatively flat and simple. If you want to heavily nest configuration it can quickly get difficult to read. I’d love a more limited version of TOML that restricts the nesting depth.