How could humanoids remain a dominant configuration through billions of years of evolution as depicted in TNG? Seems like various forms would have plenty of time to develop multiple eyeballs etc. Humans are unique among primates in our upright stance, as opposed to the quadrupedal gait found in other primates. Was that supposed to have been baked into the cake in the TNG universe too, or was it considered an inevitable part of developing sapience?
I always thought Ursula LeGuin's Hainish Universe was a more sensible/plausible premise, where one species seeds itself throughout the local area of the galaxy in various ways in the past few million years - combining its DNA with that of local primates on Earth, for instance, thus humanity's aggressive streak as compared with other intelligent species.