Well, "Conspiracy" was a conclusion of a story - the one vaguely introduced in "Coming of Age". Carrying a storyline across more than two episodes would probably not have occurred to the writers, what with it being so damn difficult to keep things coherent even as was. But any of the later Season 1 episodes could have launched its own two-story arc:
-"TNZ" could have been followed up with Romulan or new-and-scary-adversary stories.
-"Heart of Glory" could have expanded upon the Klingon Honor Movement in a sequel (and it sort of did - Worf suddenly jumped to the forefront of TNG storytelling - but only much later).
-"We'll Always Have Paris" could have done what "The Naked Time" once failed to do, and what "Time Squared" would again fail to do - turn the incidental element of time travel into the central plot of a sequel.
-Heck, even "The Arsenal of Freedom" could have ushered in some character development, a bit more on Minosian weapons on the loose, whatever.
Only "Skin of Evil" was tightly written to be totally concluded in 45 minutes, and the point of "Symbiosis" was that our heroes created consequences but wouldn't need to revisit those because they were the problem of the villains now...