My Cheese Grater™ is 7 years old, and was the last model offered before this one. I've been hanging out for years for Apple to continue the line. The trash-can diversion cost we who've been waiting an additional several years, and at the same time tested our loyalty to and faith in Apple to resume producing something more along the lines of what we wanted - something eminently-upgradeable, sporting PCI slots and not requiring that we farm all the usual internal add-ons out to TB chassis. Apple has delivered such a machine now, the only "missing" aspect of which, for me anyway, is the ability to stuff it with SATA spinners, which would obviously need to be housed as I described.
So, pretty much all boxes ticked except for the ruddy price. If a few corners could be cut and a more-utilitarian graphics card offered in place of the fancy one, along with perhaps other "downgrades" I'm not aware of the possibility of, this thing could be offered at a price point we lowly musicians could buy into and then upgrade as and when funds permit.
I'm perhaps naively hoping something along these lines could happen in response to the pressure I'm certain will be applied to the company by (mainly) musicians in the intervening months before its release.