Jaws

To me Chief Brody's story is under-developed.
His story to me "a weak-willed man moves to a peaceful town and has to prove himself to the locals of his value when a strong-willed shark threatens their local economy and way of life." While his character does arc from weak to strong-willed. His relationship with the town's people isn't illustrated. The ending doesn't have a scene in which the towns people "crown him" and it fails to revisit Kitner's mother. 

Alex Kitner's death illustrates the cost of being weak-willed.  And his mother, should have been in the "Resurrection" stage of the hero's journey to remind us of this cost.

Also, a backstory incident is never clearly brought above the surface. I felt like this hero's journey type story, excluded: The Road Back. Resurrection Hero. Return with Elixir.
Inspite of those missing pieces, I feel the movie is enjoyable. So it seems possible to have missing story pieces and still have an enjoyable movie