George Lucas is a brilliant idea man who can't write dialogue and has become an embittered micromanager - I think many of the concepts for his mess of a prequel trilogy have some kernels of genius, these naive little space yarns or quirks that only he could think up, with the internecine, labyrinthine world-building, but he is utterly unable to execute those properly himself by his lonesome, and never has been able to. James Cameron, for all his dust-ups, is also a brilliant idea man who can write the shit out of something, not to mention work it out practically for the shoot. He can do everyone's job, which is why he is that arrogant.
George Lucas cannot do everyone's job, but is rich enough to believe he can, and to surround himself with people who let him think so.
