All hard (but honest) LaTeX fans may enjoy reading my old post about LaTeX, which is somehow loosely related (I hope I'm not overstretching it :>).

Getting things done in LaTeX (or not)

http://abyss.przemoc.net/post/28208254393/getting-things-don...

Surely any modern complete (La)TeX replacement would be a good thing to have, but I haven't found out any yet, so LaTeX IMHO still remains one of the best choices when it comes to writing/publishing stuff.

I think that reStructuredText could be a nice foundation for some more generic writing/publishing solution, where TeX notation could be still uded for math environments (as I don't know any better one for that). Markdown is too vague, imprecise and inflexible, and CommonMark - a strongly specified, highly compatible implementation of Markdown - is not much better, mostly due to Markdown compatibility.

EDIT: AsciiDoc could be also used instead of reST.