I work on a lot of fairly large wordpress sites. A cool feature I think would be nice for the wordpress team to possibly note for the future would be this:
When editing a page in the wordpress admin having a sidebar widget on the right hand side (ideally under or in the publish box) with a list of sibling pages. This would make page navigation much faster. Rather than having to click all pages, then navigate to the next page if in the same area, it could be one click away if its a sibling page.
Just some food for thought.