Essentially I want a system where the configuration files are generally transparently editable by non-programmers. Most of the information is simple configuration information.

Lua, Javascript, VBA and other such languages might be called "configuration languages" but they're really object-automation languages. They allow a user to write standard-imperative-programming macros which address the underlying objects of a given system. They don't provide simple, clean facilities for just assigning default values to objects.

And what I have my configuration doing aside from assign default value is more-or-less filtering into and put, specifying tree-transformation commands for various inputs and output using one big, recursive loop and a bit of if-else logic. Basically, I'm producing a system which can take multiple web API sources and have them look like a single source. I began using XSLT but when I started having to also transform json, having my own transform system looked just as easy as transforming json to XSLT and then further adapting XSLT for my purposes.

I could use json or XML for my underlying data storage format but it is too verbose for easy human readability so instead I use simple ini format with just a bit of syntax added and it works quite well.