I have grown used to being able to click in the scrollbar background area to page up or down, which I tried to do when I determined the mouse wheel scroll down was going too slow.

And when the scroll indicator widget is over the dark part of the first graphic in the introduction, it is lost. Since there are no up and down arrow keys at the ends of the vertical scrollbar, if I did not know where the position indicator was, I am not sure I would be able to find it.

If it helps, the differential in the scrolling direction to click of the scroll wheel is two to one. Scrolling up one click covers the same territory as scrolling down two clicks.