They haven't been only focusing on one nation. There are themes from all over the world already, including what's offered in boxes and crates. It is very hard for s8 to represent every single nation around the world, there are so many, and they are doing what they can.
To stay on topic, I still hold out for an ancient Egyptian theme. I'm surprised that hasn't been done yet and I think it would be very cool to see some designs for that