Story/plot size is an interesting discussion point, especially if you compare it to the movies, which is probably the closest point of comparison. I have heard, though not verified, that the typical Hollywood screen play is only about 30 pages long. I'm sure it would vary depending on how verbose and how many speaking roles were in it.

I would hope that it would produce more story-driven games, and I believe that it probably does. I read that one game only had ten hours of material in it! I would be verily pithed if I spent $60 on a game and finished the whole thing i one marathon session.