Defense doesn't need to complicated though.
Brock Spack, the coach of Illinois State, said it best I think: "The less you do, the better you are." Keep it simple, play fast, get better talent. School's like EWU, PSU, Poly, even Idaho, have to play schematic games to win because they cannot get talent like the top FCS schools. That is, or should not be the case, at programs like UM, MSU, and the DSU's. Nobody else has the advantages those 4 do, and there's no excuse for them to not consistently be amongst the top programs in the nation. The floor is so much higher than at other places. 8-9 wins is the bare minimum, and even that's being very generous.