So you think you can tell....heaven from hell....<p>We are the way we are because of billions of years of evolution. Over the last 400,000 years or so, evolution has experimented with many different kinds of humans. Most of them were way stronger than we are. A few (Neanderthals, Homo Longi) had brains which were substantially larger than ours.<p>But now we are the only humans left. Our species at a very high local maximum.<p>I would suggest reading up on what happened to chickens when breeders wanted to create chickens with very large chicken breasts. The genome is not some nice modular piece of code. It is billions of years of kludge upon kludge, and everything interacts with everything else.<p>But even beyond that---how do we know what is "better?" Imagine a bunch of homo erectus sitting around, imagining the perfect human. They didn't even have the mental capacity to imagine what "better" would be, and guess what. We don't either.