How about the Bears? Middled around 0.5 offense but worse defense in the league. Finished with the #1 overall pick. All their wins came early when the defense was higher rated than the offense.

In my opinion football is all about matchups and coaching strategies. In the last two super bowls the more defensive team beat the more offensive one. But obviously things always change.

My biggest example I can think of is when that Super Bowl where the Giants d line basically beat the undefeated Patriots on their own.