Unfortunately, I think that Cal has fell in love with the tall, skinny, athletic post player. He loves this because if they are the right type then we can switch at every position. That was the case with both Davis and WCS. If they were beat off the dribble they had the ability to catch up and then get a block. That is the case with Lee and a bit less extent with Skal. So guys like Humphries, Tai, and Wiltjer are less valuable because they are more traditional big men that are heavier footed and cannot switch in a man to man defense and are a defensive liability. However, the problem is that the tall skinny guys, except Davis, have struggled to develop a good low post game. None of them, except Davis, were able to get the ball in the post and score with any consistency. The bigger and thicker guys probably have a more developed offensive game, but they don't get the chance to show that as much because they are a defensive liability.
It is merely my lowly opinion, but I think that Cal needs to go away from the tall skinny defensive leaning philosophy and start to use these bigger players. If he doesn't use them then I don't see why he really even recruits them. If Wiltjer doesn't fit in the system then why bring him in? Still, I think the idea needs to change. It is okay to have a big tall skinny guy playing the 4, but I think we need to have that more traditional 5 that can score and we need to be able to play them and hide them on defense at times if we have to. The man to man is a solid defense, but we have to have some sort of presence down low, so we might have to give up a bit of defense to open up the offense more.