I could do a realistic grass texture that would look outstanding a few feet off the ground, but it has to work from many aspects, since it is applied over mountains, rivers - everything.The reason for the current one is that the absolute most difficult thing with this noise map is making it perfectly seamless and symmetrical, why? because as you see in games like ARMA, once you are a few hundred feet off the ground, you get repetitive tiles that are very noticing....Any way, it not as simple as you say believe me I know. You have to find Medium effect that transitions all altitudes.
Try to improve on the current noise texture - you will learn very quickly that it is not so easy.