defining large parts of normal human variability as illness is a lie, but if that's what society needs to work around its taboos against human enhancement, so be it.

I agree that it is better than not getting any human enhancement at all, but it still seems extremely distorted. If I am unsatisfied with my attention span I can get subsidized amphetamine to deal with it -- as long as I convince a doctor that my problems are sufficiently severe that I meet the criteria for ADHD. But the benefits from the drug are not at all bimodal: basically there seems to be some kind of sweetspot for dopamine levels, and moving anyone towards it will help them. Since the current discourse speaks of illness instead of suboptimality, we end up with the wrong vocabulary for doing any kind of sensible risk/benefit analysis.

Interestingly, plastic surgery has somehow avoided this trap. Why is it that plastic surgeons can carry out procedures simply because the patients want them too, while psychiatrists can't prescribe mediation unless the treatment guidelines indicate it?