Really? Of all the things that I think video games offer, "more powerful" storytelling is not one of them. A video game will never hold a candle to my professor telling me stories of his time in the Vietnam War. Or my father telling me how he met my mother. Oral storytelling, to me, will always be far more "powerful" than video games will ever be.
Play Call of Cthulhu: Dark Corners of the Earth, it tells a story better than it's source material (don't get the PC version, it's buggy and there's no patch), play the Shalebridge Cradle level of Thief: Deadly Shadows, then tell me the story telling is not powerful. The problem is very few game developers have learned to tell a story through an interactive medium, and because of the crude tastes of most of the public it doesn't usually pay anyway. Adventure games can pace the story quite well, in RPG's it's more difficult, but there are other advantages. Obviously movies didn't replace books, and games won't replace books and movies, but each medium offers something unique from others, and each can be incredibly powerful in the right hands. Btw, I didn't mean that the best game story will necessarily be more powerful than the best book (it's apples and oranges anyway), but for certain type of story telling video games offer advantages other media can't match.