I've been wondering about this myself. What happened to make him such a nightmare?

As for the concern that humans are not evolving/improving, I just started reading A Brief History of Everything, and in it the author says that the more evolved humans become, the fewer of the evolved ones there are.

It's kind of hard to explain the whole thing without getting wonky, but basically greater depth means smaller span. So, some of us are more evolved than others, and the most evolved of us will be fewer in numbers. But that doesn't mean we aren't evolving--so that's the good news. :-)