I don't think you are wrong in principle but in practice this simply wouldn't work. We don't have enough sequenced genomes in the world to train such a network and even if we did there is no guarantee that a network-produced genome would stay in the manifold of healthy humans when trying to change an existing defective genome to a healthy one. Either way it would be to expensive to find out if a new genome actually works. Finally with a sequenced genome going for a couple gigabytes I don't see us having a large enough usable data set of these any time soon.