|If we kill him, we could play Settlers of Catan on his shirt!|
In case you forgot: What is perhaps the most Catholic race of aliens of all time abducts Kirk because their overpopulated planet needs to find some way to die.
A race trapped in a tragic, unpleasant longevity is such a good hook. (See: The Man from Earth, the "Requiem for Methuselah" TOS episode, etc.) So is Kirk being brought to a fake Enterprise. And while they may be filler, watching Spock deal with Federation and Starfleet bureaucracy is so much fun I don't care that the scenes are mostly filler.
But the good hook is lost as soon as we learn that the Gideons ~value life too much~ to use any kind of contraception. You'd rather your daughter contract a deadly disease and die rather than put her on the pill? I just....what? That is what relegates this episode to Category III ("mediocre") instead of Category I ("amazeballs") for me. Of course alien races are going to have different cultures and priorities and beliefs but that one is just so logically inconsistent I can't. Also, if space is such a priority, wasting a whole bunch of it to construct a fake Enterprise seems, well, a waste.