From an Apple point of view, its not an issue of current gen tech. Its what will sell at volumes sufficient to support the product line with as little investment as possible. To the average buyer of a mini, USB 3 is current tech. An sd card slot and hdmi port is desirable. T-bolt 1 or 2 and SATA or PCIe is meaningless. The ease of opening one up and installing a larger ssd and second drive is never considered.
Unfortunately for many of us, it supports Apple's objectives, not necessarily ours.
A "larger" SSD? Try "any SSD at all" in the case of the i5 Mini. It doesn't take much of a geek to recognize that the spinner offered in the entry-level Mini is not current tech. It's perfectly possible to know enough about computers to care about what storage you are getting, but still feel uncomfortable about ripping it open and installing an SSD yourself.
I'm not asking for a Haswell Mini in a new form factor with radical changes to connectivity. That would seem unnecessary, it would make more sense to wait with any case redesign until Broadwell or Skylake. All I want is the same old Mini with a Haswell processor and acceptable BTO options. With or without firewire, I don't care.
And in case anyone feels a need to tell me how small percentage of Apple's revenues comes from the Mini, then may I ask you to please also tell me how many percent of Apple's R&D budget you think would be needed to do such a minor update to the Mini.