Genetic Engineering for creating humans of our specifications

Genetic engineering is a really amusing subject. We often read about genetics and genetic engineers revolutionizing the future with their breakthroughs in science. We also talk about how we are able to cure debilitating diseases and if we can design humans correct to our specifications.
I can only think about it as a beginning of an immortal race. But that seems far-fetched.
Could there be a day when they genetically engineer the red blood cells to contain more oxygen so that human race can run faster, have stronger muscles, and be smarter?

There is this video I came across -


Are the genetic engineers really going to design the humanity of the future? Speak out in the responses.