There's no "most optimized human". We are already that, perfected in millions of years. What could really happen is the split between multiple sub-species. For example, it makes perfect sense to do the optimization for orbital station dwellers or Mars colonists or underwater dwellers.
We’re not perfect, we’re just good enough to have survived.
There are lots of hereditary illnesses and conditions that could probably be tweaked with DNA editing, if we can identify the responsible genes. If someone can cure male pattern baldness they’ll be rich.