Shot/image, same thing to me, but i'll rephrase question if you like
In what way is a D4S image better than a D7200 image for example?
I think that it is a fruitless discussion ... it is a personal opinion
I have a D750, D700 and D7200 at the present time
The images from the D750 are (much) better than from the D7200, specially and generally in the majority of cases at all ISO's ............ comparing RAW files the IQ is better, the noise levels are far better etc., etc.
The D700 is a really good camera and some shots are up there with the D750 ...... I prefer the D700 images to any D7xxx image
The DX sensor on the D300/D700/D7100/D7200 is and has been far noisier generally and specifically than the FX D750 and D750
The D7200 is OK as a spare body but that's all ........ I would not buy another, I would buy a D610 or D750 in preference ....... I bought then D7200 specifically for BIF's and a cary around in the car .. for the larger buffer and fast frame rate, which coupled with a good card is effective
The images from the FX sensor can be improved much more in pp than the DX image can ............ DX crops can be terrible, FX crop can be really good.
simple for me, I have and use both cameras side by side ........... with good nikon glass .......ranging from a 55mm f1.2, 105mm f2.8, 300mm f2.8 ...........70 200mm f2.8, .300mm f4 .. 300mm f4 ....... to the 600mm f4 .......................used with both bodies
just my experience - maybe your is better