Agreed on Markdown's limited expressiveness.

I think the reason for programmers' attachment to Markdown isn't just about being able to operate on it in a terminal. It's about the general interoperability of plaintext.

Terminal editing is one example, but even IDEs and non-terminal text editors also use plaintext. There's also the fact that version control tools are designed for line-based plaintext. Markdown is especially often used for documentation that gets checked in alongside code, so this is an important consideration.

I would be very interested to hear thoughts on good alternatives to Markdown for technical documentation, even if not plaintext-based.