Regarding Gladwell's book, the thing about the right place at the right time being so very, very major fascinates me very much. Bill Gates being born to relatively wealthy parents and attending a school with a computer, Buffett being too young to serve in WWII and being of perfect age during major stock market booms etc etc. Munger said it was absolutely apparent that the kids he had when he was poorer worked harder in their lives than the kids that came later, and he has no idea how to change that.
The scope of this problem on society level is almost incomprehensible. Just think of all the talent that goes to waste due to a huge number av variables interacting with each other (since there are lots and lots of them in each case and they must all function at the same time to generate "desired" effects naturally the lollapallooza effect generates a negative outcome more often than a positive one).
Regarding nature being a major component in investing ability I am absolutely positive that that is the case, though that is hardly anything controversial. Myers Briggs test would seem to be a good indicator in spotting highly disqualifying traits in people, like high scores in feeling and so on.