Gladwell is a journalist and therefore must always start from the individual case and expand outwards to larger arguments. He doesn't start with the theory and find the matching anecdotes, but rather upon learning from individual examples he starts to see the larger picture.

The argument that others don't match Gladwell's theory for other individuals' success doesn't really hold unless you've looked at the cases for those "exceptions." If Gladwell discovered one situation for a group of computer revolutionaries, were there not possible other fortuitous situations that allowed for the others? Your exceptions might not be exceptions at all but might further prove his argument. Listing them without explaining how they in fact succeeded in the face of opposition doesn't really prove anything.

Complaining that Gladwell should have been more ambitious and tackled the race/intelligence question is again ignoring the way he approaches his pieces. He tells stories that suggest theories, but he doesn't try to prove a theory the way a sociologist would. He doesn't present data, he presents examples that don't prove his argument but force you to consider it. The downside is that you can always try and find counter examples, but again this isn't academia, this is journalism.

In terms of Asian success at math does Gladwell discuss the evidence this could be biological as well as cultural? Most transracial adoption studies also provide evidence for the heritability of racial differences in IQ. Studies of Korean and Vietnamese children adopted into White American and white Belgian homes have been conducted (Clark & Hanisee, 1982; Frydman & Lynn, 1989; Winick et al., 1975). As babies, many adoptees had been hospitalized for malnutrition. Nontheless, they went on to develop IQs 10 or more points higher than their adoptive national norms.

psychology.uwo.ca/faculty/rushtonpdfs/PPPL1.pdf