I wish papier would support bbcode. Then I would know exactly how to bold text or add hyperlinks to other webpages on the world wide web (mostly angelfire websites).
I don't mind that this doesn't support markdown, or have super-specific instructions, or w/e. It's a fun bit of software, and I'm going to play around with it for a while :)
I'm just answering the question of "why would you want markdown support?"