Is there some reason you're not happy with that shot?
Looks great to me considering the ISO. My D300 could not have taken a shot like that at all. Even with flash the shutter speed the shutter speed would be limited to 1/320 and without flash the relatively poor ISO latitude would have resulted in a ton of noise.
Focus is good, the little bit of motion blur probably more due to 1/400 SS too slow to freeze the action. However, the little bit of blur and the blur on some of the water drops conveys the sense of motion. I think it is a great shot taken in very difficult light.
I ordered my D800 a few days ago. If this is what it can do I'm impressed.