You mean Marshon Brooks is a quality offensive player. Who could have predicted that? I mean aside from everybody.
Brooks can light it up and does frequently enough that he will be in the league awhile. But he isn't consistent in his shooting and he does virtually nothing else. He is the type of player that a great team would love to have as a bench option because when he is on he can get you back into a game or extend a lead with the best of them and when he isn't, you just go with someone else. He is a slightly less consistent version of Eddie House and there is value in that, but that is all he will ever be.
Green for all his flaws and his lack of consistency can just do more and thus has a lot more value than a guy like Brooks. I've never thought you could rely on Green to be a first or second option on a contender, but he could be a pretty solid starter/6th man on a contender, which gives him a lot more value. Aside from his inconsistency (which is a huge problem), Green's other major problem is that he just does nothing better than above average. he is an ok shooter, he is an ok ball handler, he is an above average defender, but a below average rebounder and passer. Just a good solid player, but not a star.