There are multiple ways to define superiority. There is no such thing as free lunch. For each kind of improvement that is traditionally associated with becoming "superior" beings there definitely will be drawbacks, like some gene trait would come at cost of loss in some other area, for example some genetic disease or just inferiority in some other abilities. Also, people DO evolve even without gene-editing. So I don't see much conceptual difference between naturally evolved phenotypes and gene-edited ones. In any case I think there would be needed centuries of gene-editing before we could achieve truly superhuman forms, if it is even achievable.