i think concept art should be acceptable, but it would have to come after an idea first obviously. I don't want to hear about someone presenting the concept art and then an idea wrap around it. For instance, if we have an idea, it'd be nice to present something in a graphic style that might compliment it. It should only be used to further the creation of a story. Also, it shouldn't be assumed that if there is concept art for a story, that that story is going to be the one you end up using. Concept is what it is. A concept.