The gap is less pronounced in full-screen mode, but you might not want to give up other on screen elements for that.
Document Outline also has smaller gaps, but you might not want to work in an outline (tabs take on new meeting, for example).
You also could have top and bottom margins set at 0, with headers and footers set at 0 as well.
Might be a good suggestion to send to Apple via the Provide Pages Feedback function.
mt