Sure, there are challenges, but Yamagishi thinks game storytelling can eventually superseded other mediums. "As opposed to films, books and TV, as a medium it is more of a challenge to produce a game in order to tell a story," he says. Obviously, in theater, film and TV, the creator has greater control in how the story is presented to the view. Thus, it's easier to control the viewer's feelings and emotions.
"But in [a game developer's] case we always have to think about how players might react to each depiction of a character or storyline, and that's the part we can't predict," Yamagishi continues. "Nevertheless we have to make these predictions to a certain degree, and incorporate this into our work." He adds that this is more of a challenge.
"But if we manage to get over this hurdle," Yamagishi says, "then I regard video games as a greater medium to provide people with deep emotional and exciting experiences."
It's just a matter of getting over that hurdle.