What's innovative about WebDAV ? It's basically a design by committee standard pushed by Rational to web enable clearcase; it's a very verbose protocol and there was an entry in Sussman's blog about replacing WebDAV with a better wire protocol like Mercurial's. Getting WebDAV into SVN was basically Greg Stein's idea - he had worked at Microsoft and had observed them transitioning over to WebDAV in a big way and started pushing for its usage in SVN as well - a move that was not well thought out. WebDAV is not very popular even with some of the SVN hackers.

Berkeley DB was certainly old when it was adopted by the SVN project. It's not like the NFS issues with BDB were unknown.