I don't think it's fine to whitewash but with GITS since she is a full prosthetic, meaning that she can change what she looks like, that the major doesn't have to be a Japanese actor. I think who they picked actually works very well.
An example of the opposite happening, the live action FMA movie that the trailer was just released for is all Japanese actors when the show took place in Europe. I can completely understand why they did it, but if they wanted it closer to the actual story then they shouldn't have.