- Neither the Mac Mini nor 2019 Mac Pro are user-serviceable; you have to take your Mac to an Apple-approved repair center if you want to upgrade your RAM (see https://support.apple.com/en-us/HT205041#one and https://support.apple.com/en-us/HT208377). I guess it's nice to have DIMMs when the computer is out of warranty, but I'd like to preserve my warranty and not have to pay Apple's prices for RAM upgrades plus labor costs.
- The storage is soldered onto the motherboard in the Mac Mini, which precludes upgrading or replacing storage.
- The storage for the iMac Pro is a special proprietary design, precluding the use of industry-standard M.2 NVMe flash drives. (Granted, the 2013 Mac Pro doesn't use industry standard M.2 NVMe drives, either, although I've read that it's possible to use some standard NVMe drives in the 2013 Mac Pro with the help of an adapter.)
- The iMac Pro at $4999 is still much more expensive than the previous generation base Mac Pro, which was $2999.
- The iMac Pro is an all-in-one design. I prefer desktop computers that are not housed inside a monitor; what happens if the monitor fails?
Apple has been providing a totally painless backup solution for a very long time, and there's no excuse for not using it.
I think your issues really just exist in your head. Which is fine, because it is YOUR head after all, but these issues are not relevant outside of your head.
Sorry for the rant in advance, just getting fed up reading all these comments that make no sense whatsoever. It pretty much all boils down to people not wanting to pay for quality.
The iMac Pro is quite nice. But extremely expensive, the computer is tied and limited to the 27" screen (which I consider on the small side), you are tied to the graphics card ordered (not sure how the top choice compares to a full desktop card), CPUs are Xeons, so quite expensive for what they do, RAM and SSD are not accessible, not even the cooling fans can be cleaned (and eventually cooling fans have to be cleaned). Once again limited to external drives.
The standard iMac now offers an i9 CPU which seems to be a sweet spot, but you don't get the same graphics cards as the iMac Pro, but at least accessible RAM. For all iMacs of current design, its a $300 bill to get anything done on the inside, due to the glued nature. A non-glued iMac would become instantly more attractive. But all have in common that you are limited to the builtin screen which you have to dispose of, once you don't use the contained computer any more.
And what is a very practical limitation: they don't have any screen inputs. I would like to connect my (work) MacBook Pro to my iMac screen, but that is not possible. Sometimes I even used via VNC screen sharing out of desparation, but that sucks.