While this looks kind of interesting, I've seen a large number of things that fall into this vein, and a few concepts seem to be missing (conflict resolution being a big one). Independent of that, though, when I first started working on my book, there were two tools I quickly needed but could not find. The first being a way to save references that linked outside of the document without being part of the document (think fact checking, reference materials, etc.). The second was a way to edit the document(s) and be able to compose sections/components together at a high level. I ended up using muse mode for emacs and fossil as an VCS (the wiki is particularly helpful for collecting resources). What I ended up doing is several files on different topics, then one for each chapter and then one for the book as a whole. Then it's versioned text copy and pasted between files. If anyone has a better system for linking to references and managing the structure of the book, I'd love to hear it.
Did you consider Scrivener? I'm not sure about version control, but it's supposed to handle references and definitely handles the composition-from-smaller-parts thing. It's designed for long works. I used the windows beta for a fairly long school paper, and it helped a lot.
I had looked at it, but none of the writer friends I have had any experience with it. I'll give it a shot now that it has had a recommendation from someone who has actually used it.
