TOS Spock's brain
TOS Turnabout intruder
Good challenges. Both episodes are tough to defend. But...
"SPOCK'S BRAIN"
1. This episode utilizes the entire main cast well. (Not during a lot of the episode, but they definitely got more to do in the episode than normal.) When Kirk is trying to decide which planet to go to, each give logical, valid reasons for their choices given their areas of expertise. Uhura, I feel, gives the best observation when she asks why Spock's brain... which I think was the unconscious reason why Kirk picked the right planet. I love watching episodes where the entire crew gets utilized well.
2. Spock's brain was stolen... that is a horror concept. I love horror, and while the execution is not as good as the idea, it was enough for me to love the horror aspect of having such a vital piece of yourself removed. Particularly as a kid when I first saw this. TOS didn't dip into horror often, but when it did, I remembered it well.
3. For much of the episode, our heroes did not have Spock and his vast knowledge and problem solving skills to resolve things. This was a very rare case, and it was great to watch them do things with the proverbial one hand tied behind their backs.
"TURNABOUT INTRUDER"
1. I've noticed people tend to watch movies and shows from decades ago and judge them by the standards of today, or at least the 21st century. I think it not only detracts from enjoying the product, but is being unfair to it, as well. Look at the time STAR TREK was produced. Few shows or movies were as inclusive with their cast. How many had a black woman in charge of a highly important department? (I mean this seriously... communications is an incredibly important department. I'm certain many, if not all, current and former military reading or posting here would agree.) Or have a Japanese AND a Russian officer working side by side with Americans? Except for South America, EVERY habitable continent is represented in the senior staff. This, more than any other reason, is why I think this episode gets so much hate... because it's viewed as misogynistic. And viewing from that lens, I can agree on that point. But I feel that is wrong and unfair. Make Janice Lester a man, and it could easily be a rival from Kirk's Academy days or early career trying the exact same thing. (Hell, we have seen that before with "COURT MARTIAL".) I bet the general opinion would be very different.
2. Speaking of Lester, I actually thought it was a smart idea to have the villain be a former love interest of Kirk. And frankly, if she kept a cooler head, her plan could have actually succeeded. How many people would have gotten as far as they did against Kirk? Damned few. In this way, it could be argued this episode was not misogynistic because the woman villain nearly outwitted our heroes. That rarely, if ever, happened during that era.
3. Watching William Shatner descend further and further into madness as Lester is honestly a treat. He did an excellent job. This was a good showcase of Shatner's abilities. I must also give a lot of credit to Sandra Smith, who I felt captured the essence of Kirk in her performance. I really enjoyed watching the two in scenes together.
4. This is more of an unconscious thing, but this episode had a nice full circle callback to its very first aired episode, "THE MAN TRAP". Both dealt with an archaeological expedition.