I read your paper with great interest as I am also interested in how educational ends can be integrated into gaming means. Your point in section four. Directions about the necessity for a variety of games to accomplish a single educational goal seems right to me. I think we are reaching the stage in educational gaming where we can fine tune the games for very specific results. I recently conducted a survey of game use by K-12 teachers and found that they distinguish the types of learner they are most likely to use games with, the learning task they hope to accomplish (motivation, reinforcement, introduction of new material, etc.), and the appropriateness of gaming to a given domain. Our games will be more effective as we come to understand the pedagogical nuances of their construction.
I would enjoy hearing more from you about the relationship of story-line or plot in the context of an educational game. One problem that I have encountered is the destruction of plot in a hyper environment; similarly, the structure of the learning experience dissolves as the player makes her way through the environment. How can you map learning sequences into an experience more or less controlled by the player? (I don't want to get too far into a constructivist dialogue, here!) In any well-written story, we can vicariously experience some change that that character makes. In a game, however, this is missing. And in an educational game, there would be little point in observing a character learn something while we did not. In other words, experience can be vicarious, but learning cannot.