Sometimes it is fine to look at other projects to see their features. Have you by any chance compared Left with Texts.io? Texts.io has all functions (this little monster also has a tex export feature worth seeing) I want but a few that you guys have:
1. Preview: I just need this.
2. Not hiding markdown syntax: Texts.io adorable as it is, hides my markdown and I need to see it.
Moeditor is nice: it does tables, math, pdf, html export but no footnotes and no bibtex...
In short, I believe in Left (why that name?) and I will support it and use it.