there is projected talent on the team, so if the new coach is someone capable of using that existing talent to the maximum then you go with them. that would be a top tier coach. a middling coach will not necessarily get more out of these guys than Hoke has or will.
then there is the potential the new coach will not have a playbook that fits the current roster. then UM is back to bringing in frosh and waiting 3 years to begin seeing what that new coach will become. why would we continue the roundabout circle jerk? that only is beneficial if the new coach coming in is top tier; otherwise the cost of rebuilding would not be worth it IF Hoke was able to run the table.
your argument is that no matter what Hoke needs to go. others are saying IF the new prospective coach is middle tier and Hoke runs the table from here out, then the cost of rebuilding AGAIN is not worth it.
IF the team loses again (high probability) then this scenario changes. then the cost of rebuilding becomes less expensive in time and money.
Highly doubt Michigan goes with some radical spread guy (RR's spread is pretty far out there. Other spreads are more moderate), even if they do go with someone with spread tendencies, Morris has the feet to be a running threat like a Forcier, and Speight would be more of a spread passing attack.
There are enough highly ranked guys on the OL they should be able to find 5 guys who can run whatever offense is brought in. Maybe that's wishful thinking. But if they go more of an inside zone, I think the 5 they have now will continue to improve. If they want to go with more spread tendencies with more mobile OL, I think Glasgow find himself replaced first.
At wideout, Darboh, Canteen definitely back, Chesson as well. No reason they can't make whatever adaptation necessary. That stuff actually gets easier for wideouts as patterns seem to be more simplistic the more radical the spread attack.
Defensively, if UM does bring in a 3-3-5 defensive guy, they've got the hogs up front with Mone, Pipkins, Glasgow, Wormley and Henry. They've got the prototypical MLB prospects in Gedeon, Ferns, and/or Morgan. Outside, McCray, Furbush, Jenkins-Stone, Ross, etc. And guys to play that "spur" position include bigger guys like Wangler & Furbush, and secondary guys like Jarrod Wilson, Dymonte Thomas, etc. 4-2-5, same thing. If they go 3-4, same thing with the big guys up front, with plenty of LB talent to piece together the 4 they need. The biggest problem would be that in a shift to a 3-3-5, guys like Charlton, Poggi, Marshall, and Ojemudia become likely transfers unless the new coach convinces them that there are extensive 4 man front packages in which they can play end. But one of the benefits of the 3-3-5 is that you can run it against just about any offensive front. A 3-4 requires those 4 man sub packages in passing situations or against spread teams.
Point being, I think the transition to RR has perhaps prejudiced us into thinking that all coaching changes are just that dramatic. It's not necessarily true. Fear of a 3 year rebuilding process may be overstated.