One of the major differences is the development of the main character. But even if you have a well-structured story with a strong central character who has a backstory, character arc, and a great antagonist, there is still a difference between a drama and a melodrama. Before answering, let me offer two illustrations. Yet it won't last. In addition, both stories are structured well.
Most people today can probably relate to yuppie love.
True, they might be able to figure out what the story is about, but it would leave them cold. And this brings us to the problem of a contemporary versus a mythological character. Opposed to this is what might be called the contemporary character. This person is simply a product of the author's invention or his social environment. When this happens on a grand scale, we get a Christ or a Hitler.