I think this is harder just because even though ideals are equally subjective as physical attractiveness, there's less of an overall reference of attraction to abide by for each individual. Since it's visual perception and psychology of the individual, I'd say attractiveness would be more Generalized by the attributes of the face that contribute to trust, compassion, and gentleness rather than the overall average as most people will find that the average of each country in the reference has varying attractiveness levels. Due to this I'd say that the overall result in the theoretic average of the world, would still be subjectively attractive from person to person. Something more moral and ideal based makes sense to be most average and most attractive in the world, but only because we as humans have the same general moral taught to us, albeit in different ways across the world.