A new post, written by our own @Sir Rhosis, details Jerry Sohl's first draft story outline for "The Corbomite Maneuver," which at stage was known as "Danger Zone." Plenty of similarities to the final version, but also a number of differences.
Wow. The seeds of the story are there, but it featured a lot of extraneous stuff that would've gotten in the way. A Kirk-vs.-commodore conflict was unnecessary -- keeping it between Kirk and a hotheaded young officer worked better, since there was enough conflict between Balok and the crew without bringing in another outside antagonist. And having Enterprise crew killed in the initial attack worked against the final "It was all a test" revelation.
Obviously a lot of the specifics about Balok and the interactions with the aliens were simplified a great deal for budgetary reasons, but I feel that was to the episode's benefit, since it kept things more mysterious and kept the focus more on the shipboard tension, the crew under siege by a strange, implacable force.
I'm more ambivalent about the Albion plot point. On the one hand, answering a distress call provides a clearer incentive for Kirk to ignore a "No Trespassing" buoy and intrude into First Federation space than pure exploration. But on the other hand, one thing I love about "The Corbomite Maneuver" is how well it establishes that pure exploration is the Enterprise's primary mission, how well it defines the optimistic principle of seeking out the unknown to befriend it.