If you had a science driven eugenics programme then the scientist would say a population with identical genomes in all respects is an accident waiting to happen

If you had a science driven eugenics programme then the scientist would say a population with identical genomes in all respects is an accident waiting to happen ( think everyone killed in a global pandemic for example because of identical immune systems.... ) - ie not 'genetically' fit. ( The scientist also might question whether the goal is actually achievable - nevermind ethical ). Also depends on what you mean by cloning - if you wanted to create lots more twins then actually you could probably trivially do it today by following the existing twin process - ie viable embryo and splitting at early stage. ( https://academic.oup.com/humupd/article/23/2/156/2527545 https://academic.oup.com/humupd/article/23/2/156/2527545 ) That would be 'cloning' and give you a identical base genetic background on which to start making changes. However most people consider cloning to be taking adult cell DNA and creating a new viable embryo from that - which is tricky to do without genetic damage. The reason people want to do the second nuclear transfer approach is they want to select the DNA to used based on adult characteristics - ie you only know Mozart was Mozart when he grew up not when he was an egg. However in my view that kind of eugenic thinking is deeply flawed.