I do think Alabama is a bit more balanced on offense (though Richardson was a monster), I just don't think the defense is as good as last years and since it is a defense oriented team, I think that makes enough of a difference for me to call them not as good.
As for games from prior years, I again don't put a lot of stock in those games, but the Auburn game was 22-19. The supposed weak Oregon defense held Auburn to less points then every single SEC team on Auburn's schedule that year except Mississippi State. And that Oregon defense was no where near as explosive as this years team. Oregon put up 27 against LSU last year and while they gave up 40, that was still less than Georgia in the SEC title game, Arkansas, Auburn, Ole Miss, Florida, and West Virginia.
Just because Oregon scores a ton of points, doesn't mean it doesn't play defense. A very common misconception.