All of that was a long time ago, though, and there's a lot more flexibility in where a document can start and end up in various other formats. pandoc changes the rules entirely, and markdown seems the most "native" format for pandoc.
In short, I think I need to be working in Markdown. But, this doesn't look like the right tool for me, at all. A subscription service for a text editor just feels wonky. I don't really want anyone else in the workflow until I send it off to an editor or for print publication. And, the idea of paying for a text editor, especially one as limited as this one seems to be (though it has some neat tricks), when there are such good/flexible/powerful/free/open editors, seems bizarre.
I think I just need to find a good set of vim settings for markdown, or give Atom another try.