When I am going through my submission pile, I am frequently finding stories that are almost there. Something about the premise sounded great, but... it was lacking in other areas. Ugh.
For so many authors, I think that when they get to editing their stories, or they are providing critiques for each other, they often look only at the global concept of the story. The focus on the big picture. While this is fine for one round of editing, it is beyond essential to narrow that focus in even more on some of those smaller parts. In the end, the success or failure of the book relies on all of these components working together.