A "clip show" is traditionally a flashback episode. Characters sit around and talk about the past and only think about things we've already seen. Or, worse, they get Lucille Ball to come on and talk about the show for an hour, illustrating it with clips.
What Voyage and LiS did was to take those clips and form a story around them.
As
Alidar said, that's still a clip show, just not the most formulaic type. The term refers to the fact that the episode is built around stock footage, regardless of how that footage is integrated. It's a production term more than a story term. There are many different ways of doing clip shows; the "sitting around and reminiscing" approach you describe is only the most cliched.
One of the most imaginative clip shows ever was
Andromeda's "The Unconquerable Man." It was set in an alternate timeline where the events of the pilot episode had gone differently -- the series lead Dylan Hunt died and his betrayer Rhade succeeded in taking his place -- and followed Rhade through the events of the early episodes of the series, showing how history unfolded differently as a result. So it incorporated stock footage showing the same events happening to other characters, but the context and impact of those events became totally different.
And there are many clip shows that find ways to tell interesting and important stories driven by the reminiscences. One of my favorites was an episode of the '88 syndicated
Superboy series which involved a machine that reconstructed holographic simulations of past events from eyewitness accounts. Lana Lang used the machine to reconstruct Superboy sightings in order to determine who was always present for the danger but then disappeared just before Superboy showed up, and the machine showed that it was Clark Kent. So Lana was convinced Clark was Superboy. But Clark countered that the simulations were based on her accounts of the events, and "For you, when Superboy shows up, I'm not around." It was a pretty effective relationship moment.
The quote is shocking because "Miri" was pretty good and "Children" was pretty appalling.
I think they're both pretty appalling.
At worst, Star Trek can be cited for re-visiting some basic ideas without saving a dime:
- "Where No Man has Gone Before" and "Charlie X."
- "The Squire of Gothos" and "Who Mourns for Adonais?"
- "The Return of the Archons" and "The Apple."
- "Patterns of Force" and "Bread and Circuses."
Ideas get reused all the time. There's no such thing as a completely original concept, just an original way of putting pre-existing concepts together.
Also, a lot of those idea categories
were about saving money. TOS did a lot of stories about telekinetic characters because it's an inexpensive, "invisible" special effect -- it doesn't require any extra expense to have one actor wave his hand and another actor pantomime being affected by it. And it did stories about aliens fascinated by Earth culture or parallel worlds that duplicated Earth culture because it was cheaper to reuse existing props, costumes, and set pieces from historical shows and films than it was to design and build alien stuff.