Yes, and DS9 also brought in non-Federation people. Cardassians who were far from saints, the Maquis who the audience could sympathize with to some extent but were not exactly saints either, Bajorans who were mostly pretty nice but could be awfully opinionated and stubborn, Odo and the Ferengi who definitely had their own agendas, and then we got to the Dominion races. Plenty of potential conflicts there.I never said that Star Trek implied that humans had become biologically superior, it's their society that's evolved. And Deep Space Nine backs me up on this, pointing out that 'it's easy to be a saint in paradise'.