Hopefully sooner rather than later, I could have the same dilemma, buy a new Mac Mini or wait.
Having recently returned to the land of my birth after several years abroad, life is somewhat itinerant, thus a MacBook Air is my mainstay for now. No fan of laptops, I look forward to the day I can settle somewhere, and set up a Mac Mini on a desk again. When that time comes a new Mini would be a preferable option to unpacking the 2009 Mini that ran on my desk, mostly 24/7 for 10 years.
With the recent update to the 2018 Mac Mini, now starting out with a 256 GB SSD, it is priced a little more attractively. However, price and specs still seem more "pro" oriented, compared to what was available off the shelf for the average Joe in earlier generations.
A teacher by profession, and an amateur photographer (occasionally providing material for websites and the local newspaper), I am more average Joe than pro. I don't require great performance.
I do however desire a decent amount of on board storage on a desktop to keep records, documents I have created, material I use from elsewhere (quite a bit to supplement textbooks available in digital form now), and my photos. I also have a library of music, as well as audio for teaching materials.
Just as revisions of the MacBook range have provided a better range of specs to suit a wider range of needs and budgets, I would hope the same for a new Mac Mini, which would make the decision a no brainer.....