Just thought of something, and probably it should just be that the answer is google docs, but fuck it.
Private threads. Only one person can use them, that being the OP. Like a notepad or staging area for posts.
I know this is possible as I’ve seen it done. Why can’t threads be done that way for every body? A checkbox with ‘save as’ and a preview with a save as draft functionality a la vbulletin? Then you can work on it anywhere! Or just keep a shortlist of notes for forum use.
Useful for me, dunno about others.