Our take is - let the viewer be as passive as they want. We're making a narrative-heavy experience, just like films and TV. But we're adding an interactive twist so the viewer can change how the story unfolds. And there's no reason we can't let the viewer just hit play and watch the story unfold as-is. We encourage them to jump in, of course, but that's it - otherwise, the story goes along it's glide path till the end of the episode. And when they're done, maybe they'd like to watch it again, but make a decision part way in to see how it effects the story.
A more mainstream example would be some on Nintendo's most recent work. They've done a great job embracing the casual audience, and really pushed it in the most recent Super Mario Bros for the Wii - it actually included the ability for the game to play itself when players get stuck:
Passive vs Active is tricky balancing act, and we're probably going to need to iterate on this a few times before we get it just right. But we definitely think the balance can be struck in a way that'll resound with a casual audience more apt at consuming TV then video games.
It's worth loading up an Amiga emulator (WinUAE or E-UAE) and getting hold of them - getting legal copies would be tricky, but copies abound...
I mentioned King of Chicago in particular because it was the most movie-like of the games - as I mentioned, if you just start it, it will run like a movie, complete with rolling movie like credits, but their other games have much of the same feel to them though you had to drive most of them forward by taking actions. E.g. Rocket Ranger, Defender of the Crown, It Came from the Desert, Wings are some of their best known titles, all heavy on narration and heavily inspired by movies.