I have two concerns about the practical implementation of this sort of thing:

1. It seems like there are cases where if a rule is being used then people could abuse it. For example, in job applications or admissions to medical schools. A better understanding of how the rule relates to what it predicts would be needed.

If X+Y predicts Z does that mean enhancing X and Y will up the probability of Z? Not necessarily, consider the example of happy marriages. Will having more sex make your relationship happier? Or does the rule work because happy couples tend to have more sex?

1. It is not true in every case that we equally value all true beliefs, and equally value all false beliefs. Certain rules might work better if we take into consideration a person's race, sex, religion and nationality. But most people find this sort of thing unpalatable because it can lead to the systematic persecution of sub groups, even if it results in more true, and fewer false, beliefs overall. It also might be the case that some of these rules discriminate against groups of people in more subtle ways that won't be immediately obvious.

Of course neither of these problems mean that there won't be perfectly good cases where these rules would improve decision making a lot.