First of all, anyone that thinks most of the NBA players don't think about the money is nuts. It is a business folks, and the better you are, the more you get paid. So for me, this is very simple. If Willie comes out and puts up anything close to 20 and 10, then I'm happy, and I'll gladly pay him. Especially if he stands out on the defensive side of the ball as well. If he doesn't, then you trade him, or offer him a salary that matches his stats. I really don't care what he says, I only care about the results of his play.
If someone created a poll that asked the fans which player on the Kings would be most likely to play well in a contract year, sign a big contract and then revert back to being irrelevant, I could guarantee you Willie would get the most votes. He is the most untrustworthy player on the team in that manner. His head is always somewhere other than winning basketball games.
Even if he put up 15 and 10 this year, you couldn't trade him for much of anything at the halfway point because teams aren't going to give up much for a 3 month rental or a guy they could just wait 5 months and attempt to sign anyway. If he does put up those numbers and the Kings sign him, I would bet a lot of money that his contract turns out being an albatross contract that the Kings will wind up paying to unload.