No, no it doesn't. Are you talking about the recent movies that split the first novel into two movies? The novel Dune ends after Paul defeats his enemies and becomes emperor.
I know that, I've read them too. In the SP, and in this thread we're discussing endings to novels. No one is complaining about a series that isn't finished due to the author's death.
I mean, Dune does in fact end mid-story, which is probably worse.