Re: I really don't care that much about upgradability....
There are plenty of options for external storage, from your basic USB attached drive to a 10Gb USB-C gen2 drive or a thunderbolt3 raid array.
Granted, the new Mac Mini is miles better than some of their recent machines with just a couple of ports, but this sort of attitude does remind me somewhat of the 1980s.
:-)
M.