Re: What did we learn from the 2007 draft?
Some good points above.
Something else I think it taught us is what kind of impact the rule denying players the ability to come straight out of high school would have. There was a school of thought that said players forced to go to school for one year might see how not ready they are and stay two or three. Instead, we see a year later that a lot of the same guys who had acknowledged (or who didn't, but realistically would have) they'd have likely come out after high school if they had the option came out after one season, regardless of on-court success.
Some, like Durant and Oden, were just ridiculously good. They almost had to come out.
But plenty, like Jarvaris Crittenden, Thaddeus Young, Brandan Wright, Daequan Cook and Spencer Hawes had mixed results in their single seasons. I don't believe any reasonable person could say that another year in college (assuming they remained healthy) wouldn't have helped them almost immeasurably as they prepared for the NBA ... but they came out. And we learned that their mixed results in college didn't scare of NBA teams, either. GMs seemed to look at them the same way they would have out of high school, as athletes with potential more than as productive players.