I wouldn't go as far as NSD. I would say, however, that a high number of turnovers (and INTs in particular) can be the sign of a mediocre defense.
The preseason got us hoping that Capers had the magic touch of turning a bad defense into a good one overnight. He's improved the defense, but it's still mediocre. The turnovers hide the fact that there are substantial weaknesses (some personnel, some likely inexperience) in all three units on D.
Right now the defense has one absolute stud (Woodson), three players tending to play above average (Jenkins, Pickett, Harris, though not against Minnesota), and other guys playing average on their good days. That to me is the definition of a mediocre/average defense. Not a bad one, not a good one, just, well, there.
I still am hopeful -- because I still think it's a question of taking time to learn the new system. I don't see Collins and Kampman and Raji as average in ability. Just haven't mastered thenew system yet.
And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what is that good and acceptable and perfect will of God.
Romans 12:2 (NKJV)