An intriguing article on Gamasutra details Bioware's visit to the Austin Game Writers Conference and their resulting presentation, "Creating Characters for Games: Writing for Digital Actors." One of the few developers that puts as much, if not more, emphasis on stories and characters versus other elements of their games, Bioware outlined a change in writing methodology required for visually lush next-gen games. Unlike older, less ambitious role-playing games which furthered the story via motionless character portraits or a handful of canned animations, the upcoming Mass Effect has tasked writers with taking things such as body language and subtle physical gestures into account. It's an interesting case where the writer can rely on the graphics to tell a part of the story -- usually it's the other way around.
The article also delves into the creation of the story and how the player's choices need to be plentiful while still remaining within the framework of the overall game. Again, the digital actor can be used to guide the player down certain paths, avoiding erratic or non-sensical behaviour that has a character suddenly going from cheery to murderous after the press of a button. There's definitely a tug of war going on between the player (who wants freedom) and the storyteller (who wants to tell a coherent tale). With more realistic graphics and lifelike characters being introduced in the coming years, it's unclear as to who will end up having the greatest grip.