She played the captain of the Lakota later in DS9, Captain Benteen.

The first time they introduced the Eugenics Wars set in the 1990s, Spock called it the last world war. Pike in SNW elaborated that it was part of the escalating conflict that went nuclear as WW3 decades later.

TNG also had Vulcan extremists (trying to recover ancient psyonic weapons) and Sela must have expected a fifth column ready to defect once her thousand troops landed and gave them an excuse.

The idea was that the Klingons had joined the Federation and we'd see Klingon Starfleet personnel in the background. When they did add Worf, he was to be more frequently Data's relief than Yar's.

If you read the initial material, Data is drastically different. There is no explicit mention of being unemotional, just that he tends to speak more formally. He's supposed to be more like the Ilia probe than Spock.

Worf didn't exist at first, so Geordi the teacher with bionic vision would be the most "other" character. If they'd seen any of the early press material for Phase II, Spock's replacement there was a very junior officer.

It's definitely an industry change. Frakes has talked about how when he directs an episode now, the show's director of photography tells him to keep the camera moving.

Wesley's mom, a main character, was initially going to be the ship's teacher. They shifted her over to the empty doctor position without changing much about her. Then they made a new teacher who was also changed to be a bridge character, as the ship's pilot.

While Riker and Troi are adapted from Decker and Ilea, Beverly was more extrapolated from yeomen Colt, Smith, and Rand.

Edit: specifically, their bios were mostly about a potential relationship with the captain, how competent they were (making them reasonable mates for him), and having the "walk of a striptease queen."

Yeah, the first scene where Riker is in awe of the holodeck also says Data was in the class of 78, Riker is reluctant to accept Data's personhood (as initially planned), and since they hadn't introduced the replicators yet, Data describes the holodeck as using transporter tech in a way that sounds very clumsy and patronizing now.

After that they mostly stick to holodecks just being new on ships, and not usually controlled by a computer as sophisticated as the Enterprise's.

TOS had a proposed spin off for him, which would have ended up about his brother (played by the same actor) as first officer of a medical ship.

It would be astoundingly different after SNW.

I've always thought the Romulans weren't just the Vulcans who rejected Surak's teachings, but also any who didn't have the physical ability to follow them.

Originally it was just based on Romulans not expressing any psychic abilities, but Picard also established that sharing personal details publicly as a major taboo. That would track with them being a mix of former enemies who are concerned with suppressing the rivalries that lead to nuclear war.

And when Enterprise did that, there were fans who insisted it was a retcon. It's something people beleived since TOS even though it was contradicted pretty soon after the Federation was even established.

There are several other things that fans have been certain of since the 60s (like saucer separation being irreversible in the field or Vulcans only having sex during Pon Farr) that weren't the production intention, but this one was blatantly impossible and it's very strange.

Spock is the first or only Vulcan in Starfleet. The crew of the Intrepid would like a word.

These can be tough, since three generations of fans have worked on later shows or ancillary official materials. E.g. Startrek.com used to say that about Spock.

Lots about Klingon history: they stole warp tech from the hurq, the hurq (who came after Kahless and stole his relics) are the gods of ancient Klingon myth. Klingon warrior culture is a recent aberration (claims one lawyer whose parents were undervalued academics). Kahless lived a thousand years before TNG. That's only half the time since Surak or Charlemagne, but fans want to see him more like King Arthur or Robin Hood.