I agree that it's more important for new cameras to support old lenses than for (very) old cameras to support new lenses, but I would still like to see at least one 35mm film camera support all the new lenses fully. I would not buy it for my use (my archive of film based images that are still not digitized is already too great to consider shooting more film) but I think there is something to the magic of working in the film darkroom that I would like to be preserved for future generations. Probably the traditional darkroom is better employed in medium format though. Anyway this is not a big issue.
I love the Df concept and would like to see this product line continued. There are some minor issues that I have with the first model which put me off purchasing it for now. I don't know if I'm sending the right signal to Nikon "I want it but with these changes ..." ;-) 1. Battery type should be the same as in the D750, D8x0 family and D7x00 family. 2. Optional user-installable and officially supported focusing screens with calibration service at Nikon authorized service centers. 3. If possible Advanced Multi-CAM 3500FX II. With at least two out of these three improvements, I would buy the camera and probably feel deep satisfaction inside when using it.
I generally think the E aperture control is nice and the way to go but with careful consideration of if some additional camera bodies could be made to support these lenses. I am not entirely convinced that the E aperture works better though. I have had one lens problem with the original VR 70-200/2.8G where the aperture mechanism got stuck in the cold and would stay wide open during exposures. This was solved by service, I think some dirt inside the mechanism must have been the cause. However, now that I'm using my 300/4E I have run into a problem with the TC-14E III of individual exposures overexposed by several stops, this I have never seen before in the Nikon system (apart from that one case with the stuck aperture in the 70-200 I just mentioned). I don't know what is going on with it I should probably send my files to Nikon for investigation. It was a situation where I had just installed the TC and decided to stop down the aperture a bit and the first exposure was greatly overexposed. After that the frames seemed normally exposed. Perhaps there was a contact problem, or firmware glitch. I will do more shooting and investigation if I can repeat the problem and find the cause of the problem. When using the lens without TC I haven't seen any exposure issues with the 300/4E.