I'd be interested to see what the numbers are for players on first swing that didn't take until first strike. That is, players who swung at the first strike (at least what they interpreted as a strike). To me that, in comparison to those who took until one strike would be a more interesting comparison.
As an example, we had a leadoff hitter who was a GREAT first pitch, fastball hitter. The HC would ALWAYS have him take until he had a strike. He would frequently have to watch his pitch, and often the only good, hit-able pitch he'd see in a game, sail by. I have no doubt that his stats would have been much better had he not been forced to take. I saw this same kid hit 100 points higher in the summer, typically murdering line drives on the first pitch he'd see in his AB's. This tended to be against much better pitching than he was facing on the HS team.
In a nutshell, a coach employing the "take till he throws one" strategy is taking the bat out of his players hand. I get it for a weak hitter in a situation that warrants, but outside of that, if the kid can hit, let him hit. Too many coaches try to over manage a game. The Cubs just about lost the world series for that very reason.