I like Search and Import from Pressbooks Texbooks. I believe we need to do more work, but the idea is cool. PBTB allow us to search a Book or a Page in the installation or another installation, and import to our book. I believe is a great idea if we whant to follow the 5r framework and to allow to edit a version of the content by other users (my content is open, that´s why I use that).
That feature is not really important in a normal book, but really important in educacion, because it helps to create new educacional content for a new purpose (of course first is necesary a network of books, but one step at a time).
I do really need, that´s why I will use PBTB, but maybe we could integrate in PB and make it better.