I'd like to close the book on this topic, because I think I'm boring everyone except Brett, Jason, and Eugene to tears.
Hardball Times' theory is useful, and the research they've done is tremendous. But a careful reading of their work on the subject reveals a mere "59% correlation on BABIP for the players in their sample." Another way of putting this is that slightly more than two out of five hitters in their sample don't correlate with their hypothesis.
As they point out, their work is a vast improvement over previous work on the subject, which produced a mere 18% correlation. However, you cannot state with any kind of authority that "A will happen because of B" based on a 59% correlation.
A scientist realizing a 59% correlation and a 41% improvement over previous work would rightfully be praised. But that scientist would also admit that there was a lot of work to be done to improve the model.
What makes me nervous about these kind of studies isn't the studies themselves, but the absolute authority with which everyone speaks after they read these studies. The vast majority of comments on this subject haven't used statements like "in all probability" or "more likely than not", but have spoken in absolute terms on a matter that - by the admission of the study's authors - is far from the absolute and final say on the matter.
Getting back to Rotisserie, some of the worst players I've competed against have also been some of the smartest: players who know all of the ins and outs of the inner numbers of the game but can't cope with the fact that some players don't hew to the statistical models. This happens with even the most basic of numbers like OBP. These owners will put far too low a bid limit on a player with a bad OBP or poor batting eye and - as a result - savvier owners will swoop in and buy those players.
Let's continue to read these articles, discuss them at great length, and admire the excellent work the authors at Hardball Times, Baseball Prospectus, and other web sites of their ilk have compiled. But let's not pretend that their conclusions are absolute and final when the authors themselves do not even make this claim.