At this point I dont think D'Antoni could elevate any roster. Any strides Golden State might make offensively would be given back through a total collapse of their currently solid defense. Also he is the last coach I would trust with Curry and his iffy ankles. The novelty of Mike's offense 8 or 9 years ago is no longer novel. The pace of the league has increased, scoring is up across the board. With how much his coaching diminishes other aspects of a team the bad of his style outweighs the good by a wide margin.
He is the Mike Martz of the NBA. Started off looking like a genius, but it was largely a reflection of how different his style was than the rest of the league, then the rest of the league adapted, neither Mike knows how to adapt and he became just another lousy coach.