Max for Wall is what, about 12 to 13 million.
I think Washington should go for it. He has all the talent in the world to be All Star caliber. Needs to improve shooting, but that will come.
John Wall is not the problem in Washington though, they need a leader in that team, and unfortunately it's not him.
But talent (potential) alone, I think he's worth 12 Mil. Outside of shooting efficiently he has the tools to be good to great at everything else.