The last two I saw, most recent first:
Move Along Home - DS9:
Feels like an attempt by the show to gauge formula. Most TV shows do have to find their format or bend around it. For example, "The Prisoner" has an episode called "The Girl Who Was Death" and it bypasses the traditional formula. "Doctor Who" has "The Seeds of Doom", which is clearly a "The Avengers" script re-rigged. "Move Along Home" feels like an attempt to re-work a classic "Doctor Who" formula into the realm of DS9, with mixed results. It's a great episode for Quark and to a lesser extent Odo, and I like how the episode makes the audience feels eerie at times (e.g. the song!) but the Wadi leave as mysteriously as they enter and seem too throwaway for such a pinpoint precise purpose. Or were they sent by the Prophets to teach Quark?
Turnabout Intruder - TOS:
The episode can't make up its mind if it's being an allegory against sexism, having Lester legitimately angry, conniving and vengeful, or treating Janice Lester as being genuinely insane. Even "Spock's Brain" (and "The Way to Eden") had better plot structure and coherence. And the crew should have picked up on Kirk's new differences very quickly. That said, Sandra Smith is first rate at doing Captain Kirk and that so often gets overlooked because of the plot. And Shatner nails Lester, particularly with the vengeful aspect. TI has a rubbish plot but the acting just about saves it. SB, not so much...