Quantic Dream's David Cage, the creator of Indigo Prophecy who's currently at work on Heavy Rain, often has good things to say about emotion in games, and in a recent interview with Gamasutra, he's leveling a critical eye on the open-world structures of MMOs and wondering what "emotional value" players are really getting out of them.
He first contrasts sandbox gaming in general with the deliberately-constructed "rollercoaster" of linear games:
"From the time you're in the line, you go in the back of the rollercoaster and through the tunnel and everything is defined. We knew while you were waiting how to make the stress grow, how to make you feel something, get you scared, make you feel better, et cetera. This rollercoaster is being conceived by someone to optimise the experience".