I'm one of those that sprung for something else (am waiting on the last few parts to build a Hack Mini), so while I may be thinking wishfully, I'm viewing this rumour with skepticism.
It just seems like weird timing to finally release a Haswell update to the Mac Mini, so unless they've somehow scored Broadwell chips early I'm just not sure that this is true. It just doesn't seem worth it to release a Haswell Mac Mini now as it'd presumably have to keep a similar chassis (as a main benefit of Broadwell is the superior thermals), which they could have done long before now.
The rumours still lack a lot of a detail, unless you count the clear wishlisting/rampant speculation we've had up until now. I dunno, I just don't think it's worth anyone getting their hopes up, as I'd see Apple being perfectly happy to wait the few months more until Broadwell parts become available in suitable quantities.