[bariumbitmap]

You already have competition in the form of ReText:

https://github.com/retext-project/retext

(Unless that's the project?)

However, there are some things that ReText does poorly, like syncing between the output window and the input text:

https://github.com/retext-project/retext/issues/108

and some things ReText doesn't really do at all, such as autocompletion of citation labels, checking URLs to see if they are 404, or proper syntax highlighting in math mode.

Those kind of features tend to require doing difficult things like parsing the input, which is why most text editors don't bother.

[fizzbucket]

Nope, ReText is not the project. But it has quite different goals. I'm actually an academic in the humanities (though lots of my work uses digital tools). I got so thoroughly sick of marking essays with shoddy referencing and inconsistent formatting that it seemed like there must be people who could use things like your example of auto-completing citations; that isn't the purpose of retext at all, and its goals are much more to help people who know what they're doing.

ReText is also not very cross-platform, in practice for Linux only, although it's possible to install on a Mac with effort. It might be more justifiable to work on improving it, but the maintainer isn't interested in pandoc support, which, first makes citations very difficult, and second, means submission either to academic journals or university tools like Turnitin is more complex then it needs to be.

Then there's just little things -- like quoting verse in Markdown, which requires two spaces at the end of each line. That's easy enough to make happen automagically, but it's a feature that would never be used by a typical ReText user, or someone using Mou or MacDown, so they're unlikely to want to support it.