Former English teacher David Didau seems to have plagiarised Wikipedia in his book called Making kids cleverer. At least it's less into eugenics than his older book. The main bad idea is a central desire to shape curriculum so as to perpetuate existing systems of power.
Didau's titular thesis is that the goal of schools is to make kids cleverer, in the sense of crystallized intelligence, by teaching knowledge, broadly construed. When it comes time to discuss which knowledge, he pivots from arguing in support of cleverness to arguing in support of dead white men on the grounds that this knowledge is culturally valued—implicitly, valued by the culture he values.
I think it's possible to make an argument for some shared knowledge, in the tradition of Hirsch, but I think it's a different argument than arguing for knowledge that best helps students think more effectively in the sense of moving toward a global maximum. Similarly, the Lindy effect is about longevity, but not necessarily quality. I think it would be much more interesting to look at curriculum design by taking seriously the idea of giving students the best mental toolkit possible. This is not what Didau does.
Didau discusses the Flynn effect, and subscribes to the "scientific spectacles" interpretation that general skills with scientific abstraction explain increases in average IQ over time, but at the same time argues one-sidedly for teaching concrete knowledge, not general skills.
I do think that students can and probably should learn and remember much more, generally, than they sometimes do, but Didau is a problematic advocate, and I don't think his obsession with IQ is useful.