Changed the default sort in the document index pages to "volume" rather than title, title being rather meaningless. I also added a secondary sort key of "start-page", which means that the documents sort themselves in the order they actually appear in the volume (once the page numbers have been fixed by the print volume release).
Then I implemented a TitleSortComparator, with the eventual intention that it be used to sort the titles, excluding leading articles. It works, but I'm unable to use it on this particular project right now because all the XSLT is version 1.0, which doesn't allow the calling of an external collator. However, it's been implemented and tested on the Mariage project, and more extensively documented there.