I predict when the benchmarks come in, the 2014 mid range mini will demonstrate significant improvements over the 2012 for essentially the same cost.
Notwithstanding the dubious dual core vs four core distinction for most users, the new generation CPU/GPU/motherboard, along with a most likely upgradable PCIe bus for SSDs, will most likely make this 2014 mini a great value overall.
I especially can't yet see paying for a 2012 i7, although ram and SSD upgradable, and lose the very significant GPU advantage.
The chip benchmarks are already published. There's no way in hell that paltry video upgrade is going to make up that performance in multicore aware software. None, nada, zilch.
Obviously, some people don't use multicore aware software, but the people really interested in the quad i7 do use it. For them, there is nothing now, unless they want to spend $1000 plus more on an iMac or Mac Pro, that's beyond their needs or budget.