what's frustrating is that many (including you, I think) were saying the exact same thing last year.
Corbin isn't an offense-minded guy. That's obvious. Basic wrinkles in the O aren't there. This could be made up for if he'd commit to D, which, apparently, he won't do full-on. Sports aren't for Buddhists... the middle path isn't a sign of wisdom.
Think about this in relation to the bigs and Favors. I have heard Corbin say that he has put Fav in there at times "because we need the defense". I think this means when he has Al-Sap in there and then adds Favors to that mix. So what he is doing is admitting that one or both of his bigs, Al or Sap, are not defending well enough. But rather than yank one of them for playing poor D, he pulls out the SF and switches Sap there. So, in Corbin's system if you are Al or Sap you can play poor D and someone else gets benched. Nice.