But didn't the Shivering Isles come out in 2007? That expansion was practically it's own game with about 40-50 hours worth of new content to explore. Shivering Isles had a wonderful dicotomy about it and the characters and style was just so incredible. Oblivion may have really simplistic combat, but it has such amazing depth in the amount of choice it offers, the voice acting is incredible, the world really draws you in and makes you care about what happens to it, and it has multiple perspectives to it's combat that gives further depth to the whole choice thing. The only thing I could think of that you could bash in Oblivion would be the simplistic, repetative combat, the lack of children making it less immersive, or too much running around, which is solved by fast-travel. What's the problem?
