Configuration is a hard problem as evidenced by all continuous reinvention of configuration formats (YAML TOML XML etc). They're all "simplified" and that's why they fail at more advanced use cases. Once you get over a few syntax quirks and the tendency of advanced users to use a bunch of syntax shortcuts, which are confusing to new users, Nix is actually a very terse but conceptually quite simple functional language which has exactly the right amount of complexity to map to its problem space.