Only the Mini has been updated with Haswell.... so are you now on bandwagon of how Apple absolutely has to upgrade ? Broadwell options would have been nice to have for the Mini if available but they were not some " throw the product line under to bus to wait for" kind of option. Neither is the case for the Mac Pro.
Unlike the Mini, there won't be a price drop. Mini's price drop is far more so in riding the volume purchases of the MBA ( same CPU-GPU package in MBA , entry iMac, and entry Mini now) and in the rMBP 13" CPU-GPU options. No quads in MBA or rMBP 13" , no quad in Mini. That may change with Broadwell, but for now.