I have been using google docs since its inception, and as an attempted clone of microsoft word, it is not about web writing. With its features come many bugs, and sometimes changes that lock out previous advantages.
WYSIWYG editors have become very strong these days, and bringing a full editor to WP would only mean adding heading font sizes, and the text left or right button to nests bulleted information to create a "class" structure that is useful for Wikis and functional modeling (in preparation of programming).
Another useful authoring tool is Mobwrite that allows simultaneous editing, which has saved my life during dead-line times. This is a google docs feature, but has been ported to Moodle, as an example.
For me the idea would be to sort of "send" material to destinations, a blog being one of them, or, very commonly for me, a wiki. Downloading in RTF will allow material to go to MS Word for all its complex features which I have found to be a requirement for my masters writing.
The name WordPress does not have "blog" in it, and actually has an authoring sound.
What do you think? John