As far as I recall, there is only one child actually on stage in the whole book, and it has no lines.

And that is one of the flaws I saw. Even at 19, I knew that children throw a whole different perspective on economics, on selfishness, on altruism, on community, and when Rand never had her sexually active main characters get pregnant, have children, or even THINK about the potential for having children, I knew she had missed the main point of how a social order is constructed.
She was also unable to make her main characters truly human, because they, unlike the story, had no flaws, no weaknesses -- and the villains, conversely, had no strengths, no redeeming good qualities. Therefore they couldn't grow, learn, develop. Heroes must make journeys, and along the paths of their journeys they stumble, fall, take wrong turns, learn from their mistakes, and evolve either for better or worse. Dagny and Francisco and Hank and Jim and Cheryl and Eddie and John were all exactly the same people at the end of the book that they were at the beginning.
Now, much of that analysis was something that evolved over the years as I grew and read and learned and progressed as a writer (and a human being) myself, but even on that first reading in 1968, my own innate sense of story told me this was a flaw, that characters who don't grow over the course of events are not "heroes."
Part of that "sense" came just from looking at the book itself. Rand uses the fable of the Twentieth Century Motor Company as the device to debunk Marxism/communism, but she was unable to see that it failed because of ordinary human nature -- greed, laziness, jealousy -- which would also have destroyed her utopia if she had allowed her "good" characters any flaws. Any generosity or kindness that motivated the Stearns heirs was equated with weakness and evil, and I had a difficult time reconciling that to my own generic christian/jewish/american tradition. She was adamantly opposed to anything that suggested compromise, and yet I think that's what essentially makes the world go 'round: we all learn to compromise in order to live together.
To what extent "socialism" successfully bridges the gap between pure Marxist communism and pure Randian capitalism, I just don't know. I would like to think that there is a middle ground that takes all things into consideration and achieves something steadily approaching perfection, but I don't think we've arrived at anything very close to it yet.
But another major element that kept my "willing suspension of disbelief" at bay while reading "Atlas Shrugged" that first time was that I recognized Rand's need to rely on major elements of non-reality to make her point.
SPOILER ALERT AT THIS POINT..
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The story hinges on two elements of pure science fiction -- Galt's generator and the invisibility screen over the valley. For all of Rand's insistence on dealing with reality, she couldn't make the story -- and therefore her politics -- work without resorting to blatant fabrication. Furthermore, even though the book was written in the 1950s -- published in 1957 -- there's no television. For her to utilize technology that didn't yet exist but ignore technology that DID was a fatal flaw for me.
In many respects, I saw Eddie Willers as the book's real hero. He was also Rand's voice throughout. The fact that he was left abandoned in the desert, after having given his life -- in direct opposition to Rand's philosophy -- to Dagny and Taggart Transcontinental, Rand let him die a very miserable death. To me that was unconscionable, as a writer, to leave a main character's fate unresolved. I don't think she knew what to do with Eddie, just as she didn't know what to do with children or people who are hurt in industrial accidents or people who get sick or old. She didn't know what to do with real life. Real life is often messy and imperfect. And that made her philosophy inoperable.
And yes, Prag, I'll post this to my journal, too.

Because I am, though sometimes I'm not,
Tansy Gold