But the problem is that the difference between a Mac mini and a nMP is vast!
Perhaps if they offered a reasonable 4-6 core desktop-class i7 CPU and single graphics card in the nMP chassis, people would go for it. (For about £1500) But you have to need/want something substantially better than a mini to be able to justify the >£1500 price hike over what was their previous top-of the line quad-core Macmini (2012).
Heck, once you add equivalent storage space to the nMP you are hitting >£3000
For most people the nMP is ridiculously overspecced. It's great at what it does for those few people that need the multicore options or dual graphics, but for those hobbyists needing a multicore with decent graphics, and a bit of expandability (i.e. RAM and HD) it is massively overkill.
The 2012 Mini almost achieved these requirements (aside from slightly weak graphics).
All the 2014 model needed was to drop in the i7 quad core/Iris Pro combo from the 15 inch rMBPro as an option, and I think there would be very few complaints. That could have easily charge £1200 for such a model with 16GB RAM and 256 GB PCI-E. Essentially the low end 15 inch rMBPro without screen.
There would be few complaints I think. Given that the 15 rMBPro is £1600 and includes a keyboard and screen, this is about right price-wise.
Perhaps some would want the NVidia 750M card too (I would prefer it) and think that it ought to fit in the MM case since it does in the top-end rMBPro), but I can see that Apple weren't bothered.
I can see that they care even less now.
My take on this "upgrade" is that they are looking at the new lower level entry Mac and not the "Super Mac Mini" that many want. Why?
From talk with Apple Store folk who's observations I respect, the Mac Pro had a very good start when released by the sales have been soft since then. Thus, Apple does not want a higher version of the Mac Mini to bite into Mac Pro sales.
Hence why the new Mac Mini is "appliance" like in production and at a lower entry level price. Honestly, I'd love to see a quad-core / 1 TB SSD in a Mac Mini for around $2000. Looks like that is not happening.