The biggest benefit of going to a public high school in the DC area was being forced to interact with kids from almost every background you could imagine. This includes ethnicity, income bracket, intelligence, and social ability. True diversity is an education in our own human race, specifically the common bonds that unite all of us. Being able to see a wide range of perspectives and experience completely different cultural norms on a daily basis can go a long way to testing your own assumptions about the world.

It depends on what you are looking for. Many socially awkward "nerds" learn how to socialize outside of just academics when they are in college. If there are few outlets besides just academics, it's hard to become "well rounded" socially. I can tell you I'd rather hire a socially adept but slightly less intelligent person rather than the brilliant but incapable outside of his field person. Unless of course I am hiring a nuclear physicist, etc etc.

It can be, and there is nothing wrong with that. But if you focus only on academics you foster students that are only good at one thing. I might be cynical, but getting good grades in a class does not mean you are good at the subject material or can apply it anywhere beyond the classroom.

How many people make 6 figures for studying for and taking standardized tests every day?