My own view on this, as on every other pedagogical issue, is that better pedagogy is better for better students, and it generally leaves poor students where they have always been. That is, good pedagogy will help students, who would have learned the subject anyway, learn it better and faster. IMHO, this is an unambiguous good but, as is immediately apparent, it violates The Prime Directive. And that, dear friends, is the reason we hear no more about it.
Indeed. A recent activity I have introduced my son to, is drafting, to scale. I think the readers on this list, well, at least the male readers, remember what drafting was, from shop class, and just how much proportion and fractional arithmetic is involved. Let alone, geometry.
Other than amplifying learned students results (and increasing the gap) these activities violate the Prime Directive in another way as well. This is easier to explain by saying - Rather than trying to tell teachers that these excellent activities are bad (because they amplify the gap), you tell them that they have more pressing things to attend to. This is what I see more of and it can't be any more explicit in the policies of the NCLB. Maximum attention to the lowest denominator. Unfortunately, the truth is that all of the denominators need attention and they need appropriate attention. I highly disagree with the notion that the brighter students take care of themselves.