I think it's entirely possible that there will be no Haswell mini, as desktop performance increase over ivy bridge is negligible. I'm sad to say that like many of you I was looking forward to the promise of crystalwell graphics, but it may not come until broadwell.
On the CPU side of things maybe, but even the regular (non Iris Pro) graphics are a big leap forward over current processors, which includes OpenCL performance, potentially making the Minis even faster as more apps are updated to take advantage. Even on the purely CPU side of things, Haswell has improvements in various hardware supported features such as decompression and virtual machine performance; maybe not your average consumer benefits, but it's still a bit of an increase there too.
I mean yeah, Iris Pro is what I'm most interested in too, but I think there was plenty to recommend Haswell for simple Mac Mini update.
My hope is that Apple is planning (or has already done) a redesign, but that it's waiting for Broadwell chips, as they are even smaller than Haswell, and iirc have Iris Pro graphics as standard, possibly even a bit better. Haswell meanwhile might work fine in the current Mac Mini, but if some of the NUCs with it are anything to go by then keeping a Haswell i7 cool is still a bit of a challenge; if Apple did want to go smaller then it might make sense to wait for a smaller, more power/heat efficient chip.
If this is the case though then I'm hoping Apple can push Intel to get Broadwell chips sooner; I know it's currently delayed due to production issues, but you'd think they could still produce enough good chips to meet Apple's needs.
