My take: it's a matter of opinion. Publishers. Agents. Writers. Book Stores. Readers. All have their own idea of what works. Was thinking about this when I read Ilona Andrews, of the Magic urban fantasy series of Atlanta gone awry with fluctuating magic, making a comment in a blog which I think sums the situation up beautifully:
"A gripping book is like porn. You know when you see it, but if you try to identify the elements of it, chances are someone will come back with a gripping book that does exactly the opposite."
Want an amusing look at a successful writer's day seen through the eyes of his/her hypothetical intern? Here's a link to the blog "Interns".
So do I write gripping stories? I don't think so. I'm sort of a dilettante who writes more to amuse myself than become a great author or even a best-selling writer. Still, do have a publication date for "There Be Demons" of Spring 2014. Arcs should be ready about October-November. Then, I have to go into marketing mode to justify the investment Grumpy Dragon is making in me.
Have a big editorial meeting coming up in a couple weeks. I'm hoping my editorial board asks enough questions to fill in the holes in my storyline, characters, descriptions and all that other stuff that goes into making a readable story. In the meantime, I hoping the storyline is gripping enough not to put them to sleep.