My beef is that it doesn't have an RST writer. What I want is a central hub where I can suck in documentation that was originally in different formats and then manually edit it in a format where I can capture essential semantics and then feed it through the system again to produce output documents.

If it had that it would be a 200 foot tall giant robot, as it is it's just another documentation generator.

Something like this perhaps https://soupault.app/

Ah, you want something like pandoc, but you can manipulate the internals as needed?

Yes, and with a somewhat different focus. I wish I could throw in 1000 pages of reference documentation, align it semantically with a few pages of documentation about a particular topic and then enrich those pages with snippets pulled out of the reference material. And things like that.

Sounds like an actually good use case for an LLM with RAG.