Scarlet Johansson got the boobies so she sells the tickets. She's also white and Hollywood has a serious issue with recasting Asian roles and more or less erasing Asian actors from cinema altogether. Her casting sickens me and I wish they'd go with somebody else. Even if Masamune Shirow gave them his blessing, it's still extremely screwed up.
Any time Hollywood wants to do a big-budget adaption of such a seminal work in another medium/culture, I ask myself why. The rule of this sort of thing is that you have to have artistic integrity. You have to have a pupose. In my directing class in college, we used "Hamlet on Mars" as an example. Does putting the story in outer space do anything for it or are you just doing that for the sake of spectacle?
This suffers from what I call "Recent Adaption Syndrome". The only people who are interested in a live action Ghost in the Shell film are people who are already fans of it. If they're not sticking with the source material though, those fans aren't going to want to see the film. Fans don't like change. Fans like things exactly how they know they like it. In the case of Ghost in the Shell, it's a an hour and a half episode of a crime show with really good cyberpunk elements.
-That's not what Americans want.
-Stop erasing Asian actors.