I have zero expertise on the matter, but have read that the transition from Nussmeir’s zone blocking to Drevno’s (desired) power blocking was problematic and that Michigan relied more on zone than they wanted to in the interest of continuity – to help bring along the limited personnel they had on the OL.
I don’t think it’s beyond Frey to teach different technique, but I do think the blocking scheme is an important issue.
With so much turnover in personnel and positions Michigan is somewhat forced into a reboot no matter what scheme they move forward with. It still seems reasonable to think that Michigan is headed towards the Stanford model (power blocking) given that Harbaugh/Drevno/Hamilton will all be there. Since this isn’t an NFL team, I don’t think they can realistically be great at everything and need to establish an identity.
It should be noted that I think Rodriguez/Frey did run some power stuff out of the I-formation as a change of pace. It’s not like Frey’s going to be over his head.