Hello! I'm working on the "Improve support for book structures" Google Summer of Code project (https://meta.wikimedia.org/wiki/Book_management) and have just created a request for comment on the extension and its design (http://www.mediawiki.org/wiki/Requests_for_comment/Book_management). I would really appreciate any feedback you have on any aspect of it.
Yours,
Molly White (GorillaWarfare)