Ok, so what? Who cares if Scarlett Johansen plays a trans character? Even if it was a male-to-female transition I still think it would be a miscast, but at the end of the day it's the director's product and he can do whatever he wants.
I have no interest in seeing it because I never saw Ghost in the Shell and this doesn't exactly sound like my cup of tea, but I'm not gonna bitch about it.
Now, if there is a Trans character and their only redeeming trait is they're trans, that's lazy writing and should be called out on when the film releases.