I am not a fan of touch screens—they disagree with me because sunblock and the rear LCD are a really awful combinatio—I want an EVF option, darn it. And at 10,000' to 11,500' elevation, sunblock is mandatory to avoid frying my skin. And even without sunblock, glare off the screen is problematic., particular with sweaty or wet fingers (which happen when hiking for sure).
I know the tilting rear LCD is going to have many fans and yes the tilt capability will be extremely useful for some shooters. I do not dislike it. All good and not much downside. But for me it is a nice-to-have and not much more and possibly one more part to break, the most fragile of the camera since it could catch on things or get debris or dirt in the mechanism.
I have to use a high quality focusing loupe for most of my work, since Nikon still does not offer an EVF. This makes the appeal of a tilting rear LCD less since I have to get that loupe on top of it; I cannot focus on the rear LCD in dim light. If it stays firmly in place while tilted it might work OK with the loupe—TBD.
There is one feature I can dig: thw 2.3 megapixel resolution. This will help me a lot when focusing by making details finer.
Greater convenience in the field — Touch operable, tilting 8-cm/3.2-in. 2359k-dot monitor
Whether lowering the camera down for a macro shot or pointing upwards at a starry night sky, the D850’s tilting LCD monitor makes it easier to shoot from difficult angles. The monitor opens smoothly even when the camera is mounted on a tripod and has the most extensive touch functionality found in any Nikon D-SLR camera to date. From changing menu settings to shooting to reviewing images, it brings a new level of convenience. And thanks to the monitor’s 2359k-dot high-resolution display, you can easily check images and confirm focus in precise detail — which is crucial when working with 45 megapixels — by pinching out to enlarge.