I am often very conflicted about this kind of thought when it comes to any kind of storytelling, video game or otherwise. While it is important to keep the narrative open to anyone, I feel like it might cheapen the experience for people following the story. Kingdom Hearts 3D for example, tries to workaround this by offering recaps of what happened in the previous games, but its not the same thing as is ultimately still leaves the newcomer confused, but for a long time follower of the series, I loved every little piece of continuity I could pick up.
The Star Wars example is really apt, and I think it fine to follow in that same kind of storytelling style, but for me at least, I like it when I can pick out bits of continuity here and there. That’s why I think the Star Wars games do such a good job to compliment the movies, because they draw connections to the films, the comics, and other games. I’m not saying that good storytelling comes from a total continuity lockout, but I am a bit worried that Halo 4 might not provide the answers that of the more hardcore fans want to know and instead of stringing together a saga, it just feels like a bunch of things that happen.
I do agree though that in a game, the narrative but be subservient to the game design. The more elements surrounding the design of the game, the better the game will be.