Just got my PW. Well, this is definitely the best one I have had so far. It still has very faint color hue issues though. I remain convinced I would see this on all of them. I have to strain to really see them on this one, but I can tell they are they when the light is up very bright. It's beyond strange to me why they keep thinking it's fixed and keep calling to send me a new one.
However, on a positive note, the contrast on this one is definitely much improved, the text is darker and more crisp. Also, the light is significantly better and the background is significantly whiter. So... some positives. I was quite shocked when I put it next to my current Paperwhite, which I've been pretty happy with, but wow, what a huge difference seeing them next to each other.
This new one makes my old Paperwhite background look murky, darker and very pink. The background on this new one is shockingly so much whiter. I will be keeping this one. So they do seem to have improved the PW quite a lot since my last one, but the color hue problem persists. Albeit to a much lesser degree, at least on this particular one.