Well although I strongly believe that humans are at the peak of their evolution, it doesn't mean I can't be proven wrong.
It's quite possible that over the next couple of millennia, humanity might experience another evolutionary leap and people with exceptional abilities in water may be born.
If I'm being honest I don't see this happening, especially since that kind of evolution will only come about if humanity begins to live in an aquatic habitat. Seeing as we are land based creatures and humanity is more interested with finding a habitable planet outside of our own and not looking for ways to live under water, I strongly doubt that anyone like that is going to be born.