How would the option of being able to stream a game give us more games? How would it give us more options?
New genres, subgenres, mechanics, or franchises, for one. With so much processing power in the network, imagine what this could do for MMO's. I fully expect SGE to leverage all those data centers to create experiences that weren't possible before, thereby differentiating the service from its competitors. Ever wish for massive battlefields where each soldier is an individual player? That might be possible in the near future.