i don't know if ergonomic is the right word. i think the correct assumption is that they want to make it as light as possible while making the least amount of compromises and I think they've done that.
This keyboard is one hell of a compromise compared to the previous-gen keyboard.
Realistically, it seems to me that I'm going to need to have an external keyboard to use this machine for any length of time. There's no way they saved enough weight to make up for that keyboard.