Please be more specific and define "changes to human nature". We already make many deliberate changes to people. We raise them in a culture, educate them, train them, fit them into jobs and social roles, make social norms and expectations into second nature for most people, make them strongly believe many things without evidence, indoctrinate them into cults and religions and causes, make them do almost anything we like. We also make medical interventions that change human nature, which is to die of diseases easily treated today. We restore sight to the myopic and hard of hearing, and lately even to the blind and deaf. We even transplant complex organs. We have changed the experience of human life out of all recognition with the ancestral state, and we have grown used to it. Where does the line between human and transhuman lie? We can talk about any specific proposed change, and some will be bad and some will be good. But any argument that says all changes are inherently bad might also say that all the changes that already occurred have been bad as well.