Interesting connection between the "Enterprise Incident" and Spock's involvement with the reunification, later on.
About the ending of E.I. -- I've never really understood the meaning of the last encounter between Spock and the Romulan commander --
Spock: You underestimate yourself, Commander....military secrets are the most fleeting of all. I hope that you and I exchanged something more permanent.
She: It was your choice.
Spock: It was the only choice possible. You would not respect any other.
She: It will be our secret.
I get that they're both admitting an attraction, despite his real goal, but I don't get what choices they're talking about, considering the situation.
I believe the choice they mention is Spock refusal to join the Romulan Empire and staying true to his oath of loyalty to Starfleet.
I always liked the Klingon-Romulan alliance idea and that the Romulans were using Klingon-designed starships. As those ships were more menacing than the original Romulan warbird, it made the scenes where we see Enteprise surrounded by the three ships more ominous. (Wonder if they've ever followed up on the Romulan-Klingon alliance in a meaningful way in any novels?)
Now, as for rewatching some old eps, I'll mention one I liked much more than the last time I watched it, and one which was even worse than I remembered.
The former was
Is There In Truth No Beauty? I remember not caring for it much when I saw it last, literally decades ago. It was quite inventive to use a big metal box and lights to show the "ugly" Medusan.
It was one of the most original eps of the whole series, as it dealt with a non-humanoid species, and with our conceptions of beauty and ugliness. To Miranda, Kollos's mind was beautiful, while to Marvik esp., others were dazzled by Miranda's own outward beauty. But then they delved into her irrational jealousy of Spock and her protectiveness of Kollos. Thought-provoking.
There's still one scene I find embarassing: How Kirk and McCoy gush over Miranda Jones at the dinner table.
Now, the one which got worse with age was
The Paradise Syndrome. Totally ridiculous ep, with a tone-deaf portrayal of the Spock-McCoy rivalry, the Native American stereotypes, and the awful acting of the woman who played Miramanee, Kirk's love while amnesiac.
The only interesting thing about the ep is the revelation about the unknown race known as the Preservers. They hinted at how they might've been responsible not only for the transplanting of the Native Americans to that planet, but possibly the Romulan-Vulcan separation.
Red Rum!