Just recently listened to Spider Robinson's reading of John Varley's book, "The Persistence of Vision," on his "Spider on the Web" podcast. It reminded me of an objection I had to another Utopian story, and all other Utopian stories in general.
In "Vision," Varley's main character is a man in his late 40's, who is unemployed and decides to walk to California (in a different, recent past). On his way, he stumbles across a small commune in New Mexico. The commune is entirely populated by deaf and blind folks and their children. (Why is part of the story.)
This small, isolated community has developed a rather wonderful utopian society. They have learned to be so effective in communicating by touch that they simply can't lie to each other or conceal anything. They are utterly at peace with each other, financially self-sufficient, and of course, very happy. The hero becomes dissatisfied with his own place in this small world, and leaves. The citizens of the community develop essentially magical powers, not well-explained.
Anyway, like most utopian societies, it is absolutely possible such a place could exist. If you could create a financially self-sufficient, isolated community of deaf-and-blind folks with psychic powers.
I was reminded of reading Robert Heinlein's "Stranger in a Strange Land" back in high school. In the story, they also create a small self-sufficient, apparently wonderful society, and all is just hunky-dory, due to the presence of Valentine Michael Smith, with magical powers. The English teacher who assigned the book (it was in Creative Writing class, I think), claimed that Charlie Manson used "Stranger" as some of his source material for his ideal world -- after "Helter-Skelter," the latter being not Utopian at all.
Hence The "Stranger" Problem -- "Stranger's" Utopia is absolutely possible -- if you can come up with a multi-billionaire orphan raised by giant, psychic slugs on Mars. I'd argue that "Starship Trooper" is another such Utopia -- you need universally noble Military veterans. I'm a veteran, and I'm not Universally Noble. or "Time Enough for Love." Got a 1000-Year-Old-Man with perfect genes handy? How about perfect body repair, and reliable human cloning, and so on, and so on?
Utopias are wonderful ideas, and "The Persistence of Vision" is a wonderful story. It is, arguably, a better story than "Stranger in a Strange Land." But when the potential existence of a Utopia depends on the existence or creation of a near-impossibility, then the Utopia is also a near-impossibility -- so near as to make no difference. One assumes otherwise at one's peril.
That said, if you don't assume you can treat that Utopia as an achievable whole, there are pieces and ideas in them that can be useful and may be achievable Some Day. That is the point of SF, if one looks for more than entertainment. By the same token, Dystopias, such as those described in Johnathan Swif't's "Gulliver's Travels" and other fantasies, can contain valuable bits and pieces about mistakes in existing societies, but are not documentary, simply explanatory.
By the way, Spider Robinson reads nearly as well as I do, and gets better books. ;-) So I recommend you jump out to his podcast page and listen to his reading of this and other stories.