I currently use a D610, upgraded from D5100. I've been using my D610 for couple years, and it's been working great.
What I do with mine: I mostly do models/people photograph with strobes/speedlights. I'm not a landscape/sports shooter so I rarely to never do any other shots with it, never really need to use it in such low light situation or any situation that I need that 7 fps burst. I use 85mm prime for the portraits, and it's been working great with awesome results.
I went to Nikon site to see if they have something new that I can upgrade to. It seems that the higher end gear is made for wildlife/night sky/sports shooters. I have no need for waterproofing, gps, wifi, or high burst fps. I shoot mostly indoor, well lit and controlled. There's no rain indoor.