Ike likes to hold the ball, he likes to pound it and try to get his shot. This system requires quick ball movement and big guys that are willing to screen and pass the ball.
Ike is having a lot of trouble picking up the defensive system, he really looks lost out there. This system demands a lot on the big guys, they are asked to do the majority of the work.
But really what convinced me more than anything was a couple of games ago, when O'Brien decided to play David instead of Ike. If that doesn't convince us than nothing will.