When re-reading (insanity check) I like to have the whole document view in fullscreen.
What I would love to see is a little line off to the right with some colours and bars on. Nothing screamingly bold, just a nice understated little line that can be ignored (fade?) when typing.
The line itself would represent the whole document, start to end, little tick marks would represent sections. Possibly with the current section a somewhat thicker line. A caret <- arrow thingie for “you are here.”
While I don’t regard colours as essential, it might be nice to colour code them the same way you do for section targets, that way you could see if you were in an area that was somewhat lacking in substance.
=^x^= How’s that for a wish?