I must disagree. ToS was where it all started. It was many people’s first trek experience. It was not “too difficult”. It was exceptional. The stories were interesting, easy to follow, and they were not dumbed down or used “big words” like TNG did to make it seem more intelligent. In my humble opinion, ToS is the best place for people new to Star Trek to venture forth. Thanks for reading.

This 100%.

It was written by Harlan Ellison, and adjusted much to his chagrin. It was such a spectacular episode that it won a Hugo award in 1968. Not many episodes from any of the other series can say the same.

Edit: Oh yes, Joan Collins was the main guest star and did a great job.