I agree with you, although I guess they have to get the NO. 1 ranking because of their record. Lady luck has definitely been on their side. I have seen them a few times this year and to me they don't seem to be as good of a team as they were last year.
The defense is definitely not as strong. Many teams have moved the ball just fine on their D. They can still get to the QB, but the rest of that Defense is not at the level they were at last year. Hurts is not having as good a season as last year either.
They should have lost that Monday game against the Chiefs. The Cowboys should have beaten them earlier this year too - never in my life have I seen a team fumble 3 times and recover it all 3 times. They have had a few other very close calls this year- but they are winning those games. That is what counts.