The issue as I see it Pete is that Willard likes to play multiple zones, including the very difficult to learn match-up. A defense that is a favorite of his dad.
Then take into consideration that he switches D's in the middle of possessions and you can understand why at times we don't perform well on that side of the court.
That said, losing Sina, Mobley and Gibbs, all players who were known more for their offense then defense will help considerably.
We may lose a few points with them gone, but we will probably give up less as well.