Brook Lopez being a soft big guy is not news, but in his defense I will say that if you're going to have Humphries on the floor you might as well have him doing most of your rebounding since he contributes nothing else.
He's another one of those big guys that is just a finesse big, and people often don't like that. There is certainly value in finesse bigs, but you need another low post presence that can cover up for them physically and on the boards.
I personally would rather have Robin Lopez for the more reasonable contract.