John Varley is distinguishable from your run-of-the-mill sf writer not in that he is an outstanding prose stylist (although he is a very competent writer), but rather in that he imagines a future radically different from common sf trends. Varley's future (at least in his "Eight Worlds" stories) is one in which sex changes are as common as hair-colorings are today, and in which genetic engineering and bio-technology are so advanced as to allow human beings to live indefinitely and take on just about any form they choose. Such a future allows Varley to explore areas often inaccessible to many sf stories. Feminism, even though Varley is often termed a feminist writer, is not an issue because the sexes have reached total equality through technology. Another aspect of his stories I found interesting was that he portrays humanity as an unintelligent race, and the only real intelligent inhabitants of Earth are "sperm whales, 'killer' whales, and bottle-nosed dolphins." In this Varley deviates from sf's, especially Golden Age sf's, common belief that humanity will conquer the Galaxy.
My only reservation with Varley's writing is that I think he is guilty of the same thing many other sf writers, particularly the Old Guard writers. That is he is too up front with his speculations. His focus in his stories is too often a straight-forward depiction of how his society is different, rather than using it as a backdrop to tell a character-oriented story. This is not to say that his characters are all flat or that their stories are not interesting, but they're not usually the focus of his stories. The fact that his technological extrapolation deals primarily with sex-changes and biotechnology and only secondarily with planetary colonization and AI's is, in my opinion, the only thing that distinguishes him from many of the Old Guard writers. Not that this is necessarily bad, it's just not my personal cup of tea.
One exception to this, though, was his story "Press Enter " In this story, which is not part of the Eight Worlds universe, Varley's focus is on the characters and he goes into great depth with his characterizations. The story also deals with AI's, but this is not Varley's primary concern with this story. He is more interested in the lives of his characters. So, Varley is apparently quite capable of writing "character stories," it is my personal hope that he continues to do so in his future work.