You hit the nail on the head. Those of us complaining are the ones who would happily (well... slightly grumpily) have bought a $3000-$4000 tower Mac with reasonable internal expansion - something that the Mac Pro range used to offer. I guess a few will stump up $6000 for a tower with a smaller SSD and inferior GPU to an $5000 iMac Pro that includes a $1000 display). 3-4 PCIe slots and up to 256GB of RAM would be great - the fact it can have 1.5TB RAM, 8 x8-or-better PCIe slots and is available with a 28-core processor is of no value whatsoever if you just want a headless Mac with space for a decent midrange GPU or two.
All the rationalisation in the world won't change the simple fact that Apple doubled the entry price of the Mac Pro.
Maybe the $12k-to-infinity-and-beyond versions will be "beasts" for "True Pros".... maybe... but at the end of the day, this is just a Xeon tower who's main advantage comes from being announced before the other PC workstation makers updated their products to the next generation. Its got a lot of (wide) PCIe slots because the new Xeon chips support more PCIe lanes. The same VEGA GPUs will be available for PCs - the MPX slot idea is a neat way of avoiding a few flying power leads, but there will only be a limited (and premium priced) choice of cards. Thunderbolt (esp. as a video connection) is the answer to a question that only existing Mac users are asking. Afterburner? That's something new for MacOS-only apps like FCP-X & Logic, but nothing new in the PC world. This may be a "beast" for users already locked in to Mac-only apps (if they're still around after 7 years with no credible Mac Pro product) but I don't see it tempting new customers to Mac. If you're a "true pro" user who will pay what it takes, higher specs have long been available in PC form (...specialist machines with 10 GPUs, multiple Xeon CPUs, high-density blade servers, true rackmount systems with redundant PSUs, lights-out etc. if that's what you need) even before the new Xeons hit the shops. Meanwhile, the plea for NVIDIA GPUs has been ignored...
The display is similar - sounds like it will be great for people who currently need $20k reference displays (as long as they don't have any non-Thunderbolt legacy devices they need to connect) - but its no help if you just wanted a matching display for the base Mac Pro you've just ill-advisedly sold a kidney for... and I don't know why anybody in their right mind would defend the $999 stand (or the $200 VESA adapter that you'll need if you want to use anything else - on a steampunk-themed display that could easily have hidden 4 bolt-holes in the patterns on the back).