There was an article just a few days ago where they found the "backwards" retina has denser cells on the front side which concentrate red and green wavelengths. Seemed a bit fishy to me, but it suggests that we don't that our eyes are not optimal. Some of the other things listed are suspect AFICT because we just don't know all the influences that led to them. Arteries? Those are ancient in origin and reflect a weird balance between flexibility, getting the blood distributed, and not bleeding to death from injuries.
While I'm sure there is hackery behind all of these, I don't think humans know enough yet to claim we could do better.
While I'm sure there is hackery behind all of these, I don't think humans know enough yet to claim we could do better.