Not at all trying to shoot down your argument, RocketCowboy, but parts of it puzzle me. For starters, you are not the first to point to the single SD slot of the 7500 as a 'non-pro' feature, but I just don't get it. I shoot RAW all the way, as any pro would, too, so a second card slot only makes sense if you shoot with instant backup, which slows the serial shooting speed considerably and is therefore something I would never consider. I back up my cards daily, and that is that. The 500, with its mix of XQD and SD slots, is an odd animal anyway, and I don't expect to see much XQD support across the camera industry given how limited its support by card makers is, so this could well be Nikon's first and last XQD-supporting SLR. (Just FYI, I have a 2000x Lexar SD card in my 500 and get the camera's full shooting performance.) So IMHO, 7100/7200/7500 and 500 are the same in this department except for faster serial shooting speeds, where the 7500 clearly outperforms the 7100/7200.
The vertical grip option is indeed a difference as far as the 7500 is concerned. Whether that bothers you depends on your shooting preferences. I travel a lot, backpack quite a bit, and always carry spare batteries, so a vertical grip is essentially dead weight to me, but we all have different needs.
You refer to an IQ difference between the 7200 and 500 that I am not quite able to point to. What exactly do you have in mind here? ColorFoto, a German magazine that in my view does a much more thorough job in analyzing IQ under tough repeatable lab conditions than any U.S. publication I ever came across, gives the 7200/7500/500 the exact same scores for image quality at ISO 100 and 400, with the 7200 scoring lower at ISO 800+. This matches my own shooting experience: at low ISOs, I am hard pressed to find any IQ difference between my 7100 and my 500, while in poor light the latter does substantially better. The resolution difference between the two is insignificant - it may give the 7100/7200 a marginal edge at very large print sizes, but that difference in my view has no practical relevance whatsoever, and if large prints are what you are after, the 750 or 810 are much better choices anyway.
As far as other features go, the 7500, thanks to having the CPU of the 500, supports a number of features the 500 has but the 7200 does not, for instance Group AF (very valuable), TIFF shooting, ultra high ISOs, XGA-size LiveView, and more. At the same time, it retains, actually even extends, some of the features the 7200 has but the 500 does not, like custom user modes or Scene/Effect modes. The latter are not exactly pro-relevant, but still.
Except for the vertical grip and the price difference (which naturally we need to keep in mind here), where do you see the 7200 having an edge over the 7500?