Search and replace
It would be very help to have a search and replace feature to update and/or sync terms all at once in an article. The ability to search and replace across multiple articles and books would make this feature even more useful.
Another related feature that would be helpful is a dynamic glossary (similar to labels). So, you could have a glossary page with terms you specify, and have an insert term function in articles. This would allow you to change a term in the glossary and have it dynamically update the term across articles. Terms inserted into articles could also be links to that term in the glossary page.