The one big thing I'm hoping the co-op/multiplayer provides is splitscreen/local MP. That's been my biggest frustration with a lot of games recently. They give you an MP option, but no way just play locally with a few friends. Everything goes through XBox Live, which means that you need an Xbox for each person, which is a bit impractical. Splitscreen would at least give players an opportunity to share the ME experience with other without needing to buy tons of stuff so people can all play in the same room together.