Duffy was great, but ended in scandal. A big part of his winning was his (and the school's) willingness to go into the south to recruit African American players. I don't want to dock him for that, I feel like he does deserve credit for it, but a big part of that was MSU's willingness to allow him to. It wasn't like it was particularly innovative as much as it was progressive. I actually think it almost has to be Dantonio to elevate the program at a time when so much of what your program was had been so settled, and to do it at a time where MI as a state was losing population. His recruiting base was shrinking, and he grew the program.
Biggie Munn probably did the same thing, and really to a higher level, one that set up Duffy's success, but he was only there for 7 years, and only the last of which was in the Big Ten. He finished with three straight AP top 3 finishes, including MSU's only AP National Championship in 1952. I think if he had stayed longer, it would be him.