I would like to see the "Pages" view on the left hand side enhanced into a hierarchical structure to support sections and page grouping. The purpose of this request is to increase usability and scalability. With a 200 page book, being able to logically group pages together would enhance navigation and moving things around as a group.
Specifically, I would have two types of folders including section and page folders. Section folders would control the section settings for everything contained in the folder. Page folders would be for users to pull relavent pages together like a chapter in a book. The user can create a section folder and access the section settings by double clinking on the folder. Section folders would eliminate the need for the "Start on page" field in the section dialog. Section and page folders could be nested within each other allowing for enhanced layouts.
The current implementation of sections obfuscates what pages are affected by each section. Applying a visual representation to sections clarifies the scope of sections and this makes it easier for users to navigate and manipulate their document.