I think it has to be the Gilroy factor. It's the only thing that makes sense. He's so revered, and has such a reputation, that they probably did anything and everything he said. While Harold is so green that he probably caved to whatever Lucasfilm wanted to him do, and Chow was similarly game to keep the budget low, having never worked in features before, only TV. In short, I bet Gilroy pushed back while Harold and Chow essentially did as they were told. It's also clear that Chow is about as artless as they come, and is in no way a visionary. Whereas Gilroy is an Oscar-nominated filmmaker with an actual point of view.