Miami has been pretty stable in their assistant coaching staff, but this season they've got two new coaches. Hypothesis I'd have is that Blasi stuck too long with assistants he had around for a while.
Also, their recruiting ground is mostly Michigan, with secondary sources in Ontario and Ohio. (And a few from all over.) I wonder if geography and time zone differences may be offsetting the NCHC advantages of playing against top notch competition to set players up for a shot at the pros.