This is actually part of a book I'm writing. In my view, the audience feels a series of emotions throughout the moviegoing experience, but their final emotion or feeling should be satisfaction, i.e. that they have participated in an entire and well-shaped story (in the sense of "story" that you have defined elsewhere so perceptively). The ending may be open or ambiguous or tragic, but the audience can still feel (and MUST feel) that their investment in time and perhaps money has been worthwhile.

I know the above response is vague, but there are ways to determine if the script is "entire and well-shaped").