My issue with the computer is that it's purely for that market and they created a base model which makes no sense... it's got a slower CPU and the same GPU as an iMac 5k (non-pro) for over double the price. Yes there are a bunch of other features but they aren't ones that will matter to a decent chunk of Apple's "Pro" market.
I knew a decent number of people with the cheese grater MacPro who were freelance photographers and designers. It lasted some of them for a decade and its' upgradability was key for it. But that computer was comparable in price to PC's and could be had for 2-3k. I doubt it would happen but a Mac Pro light with say only 1 10GB ethernet port, not as many PCI expansion ports and use just traditional ones, E series Xeon CPU's, 4-6 DIMMs, and a 650-800w power supply could do it and that wouldn't be hard to create and could still be sold for a premium. Those E chips are already at 8 cores and with AMD going to 16 at that size they'll likely be there in a generation or 2 so it would have the performance needed for most photographers and designers.
And that brings up the other issue, this will be coming out after Ryzen 3 and the PCI-4 NVME's that it supports. So by that time you'll be able to get a AMD based computer with 12-16 cores that has similar per core performance, a faster GPU (RX590 or Vega) from a major manufacturer like Dell for 1300-1500 dollars and probably under 1k on sale. It's not Apple, and you lose ECC memory but it's hard to stomach paying 4-6x as much for a computer with slower storage, a much slower CPU, and a slightly slower GPU.