Now you’re scaring me. This is quad-core Mac Mini going away so you will be upsold to a more powerful system (an iMac in that case). If the top current iMac is removed so that I have to buy an iMac Pro to get equivalent or better power then Apple is pulling the rug out from under me. Refurb iMacs aren’t sold in the Apple Store of the country where I live.
Being upsold was always the plan with Apple but I think there's legs in the iMac Pro concept in general and later on down the line Apple could go with Xeon CPUs if there is a suitable range at decent discounts to fit the 'professional' lineup they might have if ARM CPUs for consumer grade Macs are the plan going forward.
Launching the 2018 iMac closer to the 1 year anniversary of the iMac Pro makes it possible but unlikely that the iMac Pro gets a refresh at the same time (to get FaceID if nothing else).
The iMac Pro came out in December though and there's no other hardware that could fit into the first generation unless they are bringing out a lower priced SKU which is why I would have said that Apple could go a different way with the non-Pro iMac.
Xeon E CPUs in an iMac Pro would largely mimic the 8th generation Coffee Lake i7 so why offer an i7 option in the cheaper machine? Especially one which people would just add their own memory to?
My idea would be i5 CPU with 6 cores - which would be a horsepower increase on most 7th generation i7s doing multi threaded work - and bring in a Vega SKU to help fill the other 30w TDP which removing K series CPUs from the consumer iMac might offer.
Apple would create a lower priced iMac Pro SKU by introducing a 24" 4k panel but not 21.5" professional spec which seals the RAM in and introduces FaceID as a party trick (to be added to the second generation iMac Pro in due course).
So our iMac range looks like this:
21.5" iMac Retina DCI 4k starting with i5-8305g CPU (4 cores, 8 threads) and captive RAM
24" DCI 4k HDR iMac Pro with Xeon E, Vega 28/32, SSD only and captive RAM (6 cores, 12 threads)
27" iMac with i5 Coffee Lake and Vega 32/56 GPU (6 cores, 6 threads)
27" 5k iMac Pro with Xeon W, SSD only and captive RAM (8+ cores, 16+ threads)
A fully loaded low-SKU modular Mac Pro could also be offered around the price of the current 2013 Mac Pro.
The
7nm AMD Vega Instinct GPU will be with AMD partners by the end of the year - clearly that's going to be an option for modular Mac Pros.