The current Mini is a bargain
I agree that the 2012 Mini "ought to be good enough for anyone" today. But if I buy a computer today I do it to run software comfortably on it in 2018-19, and the chance of that coming true would be greater on a 2014 Mini than the 2012 Mini.
Regarding Intel messing up the Broadwell timeplan, that does not change the fact that Haswell exists and Apple has chosen not to use it in the Mini.
However, I do realize that Apple has other priorities than satisfying every wish from the likes of me. The margins from selling the 2012 Mini for 2012 prices in 2014 must be pretty good. Who knows, maybe they make more money this way despite losing some customers who want current hardware.
It looks like OS X 10.10 will run on Core 2 Duo which came to the Mac Mini over five years ago, and iMac earlier. There are some apps (Aperture, for instance) for which more recent hardware is recommended, but most will run on the older models.
Based on history, a Mac you buy today should be good for several generations of OS X updates. I would not worry that the current Mini will be obsolete by 2018 - 19.
Where I am, at least, the 2012 Mac Mini is a much better deal now than it was in 2012.
Based on inflation running at about 8% where I am, it is pretty good that the current Mini is still selling at the 2012 price (19,900 baht)……
And it now comes with iWork loaded, so is ready to use, whereas previously productivity software was an added cost.
A new Mac Mini now would set me back about three week's pay, and be ready to use.
My base model 2009 Core 2 Duo Mini (23,500 baht) cost me about a month's pay with added the cost of iWork (5,000 baht). An extra 4 GB of RAM and Mountain Lion were extra costs (4,000 baht) incurred in 2012. Over 5 years old now, it will still be good to go with Yosemite.
My original 2005 Mini (26,500 baht) was more than a month's pay for just the computer, and I forget how much it was to licence the apps it came loaded with.