Latest try at a swim meet. Not as frustrating a venue as the last and was able to shoot w/o a flash. I usually shoot on shutter priority, but tried it on manual w/f4.0, SS at either 400 or 500, auto white balance and auto ISO. I think the SS was a little slow but it seems to work for these pictures.
Those are very nice. I tend to agree with you about the shutter speed. You're getting a little bit of motion blur, such as in the hand in the third shot (which I really like), yet the SS is fast enough to freeze most of the water motion and keep the faces sharp. It's a good effect.
I like the second and third shots. Not sure what you shot these with, but you have some fine equipment/glass. If I had your equipment, I'd use the 70-200 and open up to f2.8. This should get you an extra stop of speed with no more noise, and solve your motion blur problem. I actually find very little objectionable blur in these. You don't need much DOF in swimming, since only a fraction of the body is actually above water, and you should be able to crop a little tighter with a D4.