I would suggest the following feature: commenting out text. It is very similar to the programming languages comment style where you can do something like this:
This is my well written paragraph, and I think is cool.
This is my messy paragraph that has some cool ideas but is not yet ready. So I can just write and don't care if I mess up the document.
Here is more text that ready for publishing. Great text.
When I publish this, the "comments" will be just ignored. I used this in latex and it was very useful.