A little too late in my case. I was waiting for the D400 back then but came to the decision that it will never come about back in 2012 and jump on the D4. This D500 is impressive with the new features but having moved on to the FX, I see little reason to consider it. The added bells and whistles taken away, the improve IQ due to a new processor..etc, a camera like even a D7000 is able to do the job. For 90% of shooting situations that don't need the fastest action AF speed, tracking very complicated subject ..etc The Nikon Df is more then up to the task for a few years to come if you buy one now.
At even this point in time, I think the D810/D4s are still good enough cameras for pros.
But as someone also mentioned here, the D500 will be popular with wildlife shooters looking to save on lens price versus focal length issue.
As a Canon user who used to own the 7D2, I can see that the image quality from a FF and crop sensor are non-comparable, so actually a crop sensor cannot be used to replaced focal length directly IMO.
I would say that serious hobbyists/photographers should look at the D5.
Serious hobbyists/photographers usually are more particular and are willing to pay more for those "extras" but ofcourse for many the slight difference in IQ and features is nothing compared to the price difference between D500 and D5