UPS was just here and delivered my replacement. Is new of course.
The screen while it is still gray, it's a light gray and does not have a gray cast to it and that makes a world of difference! It's still not as good as my K3 screen but the text looks black enough for me to be happy with it. I put the two K4s side by side and you can definitely tell a difference.
No white lines after moving the menu selector down either and the page buttons are looser so I can actually use one hand to turn the pages. The power button is also better so it takes no holding down to turn the Kindle on. It clicks with one push then the old one took some force. So far I am happy with it.