I don't think they were at all saying that teachers are replacable. Infact, they applauded the audience member who very emotionally asked for the 10k it takes to develop a game to be used instead to increase the salary of 10 thousand teachers by 1k each (though that hardly rewards them what they're worth). The education system is not failing because teachers are underpaid. The panel was looking at why it is that learning is no longer engaging and motivating students and developers are arguing that perhaps videogames are the solution. The panel discussed at length the importance of teachers as facilitators in this new game-learning environment. They were more concerned about issues such as learning assessment and the importance of integrating the goals of curriculum into interface design.
The strongest point I think they had was adressing the differing levels of the various students in the classroom and the strength of videogames to detect skill level and increasingly challenging the student from their personal level upward. Another strength the panel mentioned is the ability to relearn a concept that was at first try, difficult to grasp. While classroom learning moves on at this point, videogames allow students to repeat skill sets they might need a bit more practice on.
I agree that videogames should not replace the current system completely. But I do thing it should be a substantial component in education, to engage students and make them comfy with technology.
More to come on this. Interesting stuff.