While the D500 is a good camera, I really question rather or not it is worth twice the cost of the D7200 unless one is exclusively into sports/action photography. It was a decision I faced when I got my D7200 and the D7200 won out and I have never looked back.
There's two sides in a DSLR, the
digital part and the
camera part. People often concentrate too much on the digital part and tend to overlook the camera part, IMHO. The digital part between D7200 and D500 is a wash for all practical intents. The dynamic range, low light performance (including noise) and image resolution are all within a few percentage points. Linear resolution difference is 7.7%.
But the body design and features are often more important, at least to everybody I know. The body could even mean the difference between an image and no image. If you get no shot then who cares how many pixels and how low noise your camera has?
The D500 has more configurable buttons, larger viewfinder, better AF with wider AF coverage, faster frame rate, deeper buffer and so on. And for a 6'5" like me the better grip with more finger room is a deciding factor. All these add to better haptic control of the body, being able to shoot and keep on shooting without removing the camera from eyelevel, changing settings on the fly with "touch and muscle memory." For some people the body design alone is worth a lot more than double price. Shooting is a hobby for so many of us, so why shouldn't it be enjoyable to the max?
Sure, not everybody uses the cameras the same way and that's why different cameras entice different users. That's the crux of free economy. But just because the sensor output is similar does not mean that one camera isn't worth 2 or 3 or 5 times more than some other body, at least to some users. Because not everybody uses the cameras the same way.