I've read that the Children of Dune miniseries, made a few years later and which is actually one episode of Dune Messiah and two episodes of Children, was better but I never bothered with it.
If you want to talk about a SF series that is too talky to film, there are been multiple aborted attempts to make a Foundation franchise. I never read the later books (which have a mixed reputation), but the earlier stories are nothing but talking. There was talk of giving them to Roland Emmerich, which makes about as much sense as asking him to remake Twelve Angry Men. And they're really a collection of short stories and short novels that appeared in a magazine and then later became a "trilogy" when they got bundled into three paperbacks because of publishing trends. They're structurally unsuited for the big screen.