I won't be surprised to see it get used a little, but it probably won't become a big thing. I bet that when it does get used, it may be watered-down - bearing in mind that I only saw a few instances of this from the short time I played RE4 so I dont know how complex it got.
Still, not all casual gamers are there to play a "movie". Of course, I don't have statistics on that (would make for an interesting but not very useful study), but of the casual gamers I know, about half love the cutscenes and about half hate them. Some casual gamers are there for a show, but a lot are still there to play games, and, as one put it, "Blow s**t up". I think the real barrier will be that most developers aren't creative enough to be bothered...making the scenes interactive means developing them with interactivity in mind, which does take a bit more creativity. You can't just make movies, you have to figure out how they'll be playable...and you also have to start doing most things with in-game graphics instead of FMV (which is a good thing in my opinion, but maybe not as far as some others are concerned).