I believe wholeheartedly that Joerger and Divac have determined what WCS's role should be going forward, but I don't believe that WCS is ok with that role. This may be a situation in which a young guy just can't believe what he's hearing from his coach or management about his role, and will only believe it when he hears it from another coach of another team. Kind of like a young adult who doesn't believe what his parent says until he hears it from a different source, or a spouse not hearing it from a spouse until he/she hears it from another "independent" source.
As others have said, he's inconsistent. When it comes to the offensive side of his game I don't believe his inconsistency is because of effort; I just see a guy who just isn't as talented in terms of his balance, agility, and touch to be first or second option on a good team. And let's think of where he would fit on a very good team. Where would he fit on the Warriors? He'd only be "garbage guy." Same thing for the Rockets, Celtics, Cavs, Raptors, Spurs, Timberwolves and Thunder. If he were traded to one of those teams, they'd immediately define for him what his role was in no uncertain terms, and because he's on a good team, he would probably go out there and do exactly what they told him to do, and he'd probably be pretty darned good doing it.
Unlike his offense, I believe his defense and rebounding is inconsistent because of inconsistent effort. We've even heard comments from him to that effect. As he gets closer and closer to the end of his contract, I would expect for his defensive effort, including rebounding, to become more and more consistent. But what makes it so difficult for me to figure out WCS is this question: What would his defensive/rebounding effort be after he getting a contract renewal from the Kings? I don't know the answer to that. Is he going to mature into a player that gives that consistent effort, or is he going to revert to his mean of inconsistent effort because now he's got the contract?