...The whole reason NBC scheduled "The Man Trap" as the series premiere is because it fit the monster-story template that so much SFTV had at the time..
Source for that assertion, please.
This has been discussed elsewhere, and it's covered in Inside Star Trek
but, as I recall, of the episodes which were ready to air for the premier "The Man Trap" was the one NBC deemed most illustrative of the "strange new worlds" concept. "Where No Man" was considered "too expository, for instance. I'm not at home this week so I can't pull the book out to cite it.