I would hesitate to call characters from anything Clarke wrote "round" in shape per se. Childhood's End was somewhat interesting, but C. S. Lewis response was more interesting. At any rate, it is not the novel that Dune is.
Found this pretty good essay that goes over the historical context and literary value of Dune specifically:
"What Accounts for the Lasting Appeal of
Dune? Michael Dirda on the Perennial Resonance of Frank Herbert's Masterpiece":
Feature illustration: © Sam Weber for The Folio Society’s edition of Frank Herbert’s Dune. Arrakis, the desert planet sometimes known as Dune, is the only place in the universe where melange can be…
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