In his defense, it's easy to say "be aggressive." It's quite another when it means choosing to look for your own shot when you're playing alongside three future first ballot Hall of Famers and Rondo.
Part of the conundrum of this team is that there are so many scorers, but no clear go-to scorer. Thus, we do need someone like Green to step up; however, how do you assert yourself in an offensive predicated on moving the ball and being unselfish?
That's not to say there aren't ways to do that within the confines of the system (there are). However, it''s a more complicated process here than in OKC, where Green had isos and other plays run for him.