Assuming your honesty and good faith on asking this question, the real treasure on our gene pool is it’s diversity. Eugenics would, by definition, reduce it. You could assume that it’s a low price to pay for health, longevity, strength, intelligence, beauty and so on, but it’s not that simple. Even some diseases (out or the possibility to develop it) can be beneficial under the right circonstances, e.g. sickle cell anemia can improve resistance to malaria.

It would be great to be able to prevent most diseases before it happens and treat it if it happens (for free, in a universal health care system), but eliminate the genes would be a very bad idea, a healthy specie needs it’s diversity to avoid extinction, and we sometimes feel like we are above that risk, but we are not that special.