The warmer screen thing does seem to happen every year... I remember when I got a replacement iphone 4 shipped to me to replace a faulty one, and the new IP4's screen was way WAY warmer. Had to take a bunch of photos and send them to Apple, and they shipped out another one. This time round I switched from a 7 plus, which doesn't have True Tone, to a XS which does, so it obviously looked different. Am very interested to see the difference between the XS and the 12 pro I have on order, when it arrives.