[_mql]

The problem I see with markup, is that for-non technical people it's hard to understand and use. I think they would rather prefer a WYSIWYG-style. Wiki-style-markup isn't for everyone. So that's why I chose WYSIWYG editing, but with restricting it to just semantical annotations.

Regarding PDF. I totally see your point. And it has high priority. I got offered some help by Kevin Lynagh (http://www.dirigibleflightcraft.com/index.html) already. He'd help with implementing LaTeX/PDF export of Substance Documents. You're invited to join too :)