Little is wrong with most voluntary eugenics. I don't think most rational people with Huntington's would want to pass it on.
Voluntary positive eugenics may be problematical unless you are an NBA star.
Have you seen the movie GATTACA? Genetic engineering is presented in a negative light (available only to the rich). I think, however, that a couple hundred years from now, conceiving a seriously handicapped child will be considered a preventable tragedy.
I don't know whether we can easily raise the maximum IQ, but I suspect we can raise the bottom and mimimize stupidity.