Actor's ethnicity/nationality doesn't matter.
I read another thread that focused on the ethnicity of the actors. Whether the creators should have chosen actors true to the ethnicity/nationality of the actual characters/figures of the story or people that actually only looked like they could be that ethnicity or from that part of the world.
In my opinion, it shouldn't really matter. As long as the actors look the part and can deliver the needed performance, its good enough. Its a plus if you can find actors from that part of the world or of that specific ethnicity to star in the film but at the end of the day, it all boils down to whether or not they can get the job done.