Defense is not optional, in my opinion, but it is true very few teams, even some that have perennially great D's, have looked good this year. UGAG, to my chagrin, has a top notch D with NFL guys everywhere. Obviously, Bama's D is way, way down. Clem's son appears to have a very good D - if they hold ND to less than 24, I think that will seal the deal about their D. Miami's O is not terrible, and Clem's son held them to less than 20.
I would like to think Kirby "fake a punt for no reason" Smart will blow it somehow, but right now, it would be intellectually hard to pick against them making the playoffs and possibly the championship game. In today's more offense-centric big boy football, a team that can get a few 3 and outs every game is going to be considered stellar. The rules are definitely skewed for the offenses, and the RPO has made playing D even more difficult.