The Broncos played the AFC West last year, too....just like every year. In the loss to the Bengals, Cincinnati actually didn't do much on offense outside of an 85 yard TD run by Hill. It had a lot to do with Manning's 4 interceptions and some poor special teams play giving the Bengals good field position.
Besides which, I'm not trying to say that the Broncos D has been great this year....just better. And with an offense that can potentially put up a lot of points, a great defense might not be needed.
I'm no Broncos fan, and I don't know if they could beat Seattle should that matchup occur again, but the Broncos defense has definitely been improved this season.
Chiefs had a much better O last year. This year they failed to pass a TD to a WR, and Jamaal Charles numbers were down. Chargers offense fell off significantly from 2013, gaining 800 fewer yards. Raiders were also down almost 800 yards from 2013.
Denver's defense was great in the playoffs last year, until the Super Bowl. They held SD to 17 and NE to 16 points. I don't see them equaling that performance this year. Colts will score more than 17.
Whatever, I'm just grasping for reasons for Denver to fail.