In one essay, Eliezer seems to be saying that Traditional Rationality was too concerned with process, whereas it should have been concerned with winning.  In other passages, it seems that the missing ingredient in the traditional version was Bayesianism (a la Jaynes).  Or sometimes, the missing ingredient seems to be an understanding of biases (a la Kahneman and Tversky).

All of those are problems with traditional rationality, and Elizeer has critiques traditional rationality for all of them. Traditional rationality should have helped Elizeer more than it did, except for one thing: His mysterious answer was falsifiable, but not until we'd developed the technology to test it which wouldn't be for decades.