I think way too many fans are casually dismissing the defense problem by saying "oh we have guys that are getting beat off the dribble and aren't hustling enough". That happens occasionally, but a way bigger issue is our philosophy on defending screens.
I'm not sure when we Cal started doing this, but we go over every single screen, whether that is on ball or off ball. We hardly ever switch or go under them. We used to switch everything with our elite defensive teams. When we go over the screens, it puts Mitchell/our bigs in a horrible situation trying to defend 2 on 1, and then the rest of our guys panic and collapse the lane for easy kick out 3s, or the initial guard just goes all the way in and scores.
I really don't know the solution to this other than hoping Cal starts guarding screens differently which I don't see happening. I guess we pray that our backside rotation defense gets stronger, we actually can block a few shots at the rim, and we can cut off the drive and kick lanes for 3. But I'm not optimistic.