That is substance. People's lives are affected. The ideas take physical shape and conflict with each other. Take any of these away and there is no story that will sell. But where you start writing will determine what is emphasized in the story.
Idea driven stories focus on form.
A good plot will sell your story faster than good characters. The writer who writes about ideas has to go to greater lengths to include events and impact. For all three types of stories, the chemistry that makes the audience relate is the character and what happens in their lives. So characterization has to be done very early in the process of creating a story. Also during the process of writing and rewriting, a concept can be constructed which will prevent the story from going in all directions.