There are lots of opinions on Days flaws and assets and where he needs to tweak/overhaul to turn the rivalry back around in our favor.  I personally think most is a great way to kill time in offfseason and keep us engaged as fans but should not be taken seriously because so much of the difference between success/failure is very ambiguous and can turn on things outside any coaches control.  This rivalry was never going to continue in the direction it had for the prior 20 years, no matter if Utban was coaching or not.  Michigan plays football at too high a level for it to continue and many of our previous wins turned in weird ways from things beyond the coaches control.   Mainly, in my view, the supposed QB whisperer Harbaugh couldn’t find a QB not to self destruct at key times, and the only reason he has one now is cuz Day didn’t want him!!!  Talk about Karma!   JJ really has been Michigans Troy Smith, kid is just a gamer it seems.  Outside of this it seems there was something I read by someone in a comment somewhere that I think has some merit ( sorry I can’t properly attribute). It was mentioned that Day needs to look for some help with tweaking the offense and S&C from someone outside the Chip Kelly tree.  
 

Chip Kelly was vastly successful at Oregon with his unique program and approach.  No one can dispute the results he had there but everywhere else he’s been it has not been nearly what was hoped for.  I don’t know too much of the details of his methods but they obviously did not travel well.  Was it because the other places weren’t committed enough or doing it right?  Was it because of factors beyond control of Chip ?  Idk.   But I do think it’s failure to reproduce results is a mark against them as something that can be universally applied.  Now idk how much of Days methods are Kelly methods. How much of a disciple is he?  This might be worth examining. I know Frye was at UCLA but do we have others who can be considered disciples?  I think every coach has to find their own way and will take influence from many places but it’s always smart to “examine your priors”.  What are you taking as an assumption that might need to be revised?  
It’s presumptuous to suggest that Day is t doing this as we speak.  He’s a smart guy but in the changing game of football I think the good ones constantly revise. He needs to be a disciple of himself now. Take what works from Kelly or anyone else but throw out other stuff

Look at Saban. 10 years ago all his QBs were Greg McElroy types but since Hurts and Tua they have had a complete 180 except for Mac Jones. From  defensive oriented teams to dual threat QBs, from defense that had to hold you under 17 to one’s who just need to give up under 27-30 to win