The argument is between form factors, not exactly hardware. For most people who relied on upgradeability of the computer, loosing it is painful.
Both computers as you can see have their drawbacks. Both are currently non upgradeble.
You are the one that introduced the hardware saying Apple could upgrade the hardware in the Tower if they wanted too, I didn't say anything about the Hardware being changed/upgraded in my post that you responded too. I simply pointed out that neither box would meet the requirements as are. Which we have agreed on.
Lets make it layout. as you and pl595 want, and not the hardware Theres nothing in the LAYOUT of the nMP that means that it cannot do upgradeability, as that is what you are commenting on. There is nothing in the Tower/cMP layout either that prevents it, of course there isn't.
iFxit did a tear down of the nMP so if you can tear down then you can put back together. This would therefore allow the LAYOUT to take better cards ( if there are cards available, however we are talking LAYOUT not hardware now) when reassembling would it not.
What is now available in PCI-E that you cannot put at the end of Thunderbolt? There are people out there with eGPU's.
Yes Thunderbolt has disadvantages compared to a PCI-E slot however those are Hardware Disadvantages not Layout
If you want to make it LAYOUT then all that you have with the tower based on layout is that you can fit more physically inside a Tower the size of the cMP then you can inside something the size of the nMP, and that is easier to work on.
I seriously doubt that ANYONE that voted No on here would actually dispute that.
At that point once you remove the hardware inside you are surely down to how it looks, or dare I say it Form over Function!, in that it looks neater wrapped up in a single case under the desk, ( my desk which has lasted 25 years so far, I wouldn't trust with a loaded cMP and the 30" Dell ) as opposed to several boxes connected by cables ( depending upon what you need to add to your System ). Both layouts would allow you to do exactly the same work, it would simply be that one looks neater then the other.
So we have had 2 years of I want my Mac Pro in a Tower because it looks neater internally, rather then externally! I can understand that perfectly. ( I say two as end of 2013 to beginning of 2016 isn' 3 )
Apologies if i have misunderstood what you have meant by its about the Layout/form factor, not the hardware. There is of course no reason that updated hardware COULDN'T have been put into the cMP Form factor. There is no reason why updated Hardware CANNOT be put into the nMP layout.
The problem appears to be merely that Apple HAVEN'T done either of these two things.