Watching the keynote with Frank and Kiki, and came across something at about the 14 minute mark that I really don't like if I'm interpreting this correctly.
Going to paraphrase Frank here with my interpretation, if you read this Frank, feel free to correct/elaborate:
Frank is talking about the connection between the books and games, and specifically about the Didact, and what he's basically saying is that book readers get to fully realize the character, and people that don't get enough information to "know that he's the bad guy and you want to stop him". Leaving meaningful narrative out of the game (same thing with the Didact's story being hidden away in Terminals) is a damn shame, and I think a huge mistake. Yes, Halo is a transmedia IP, but the core is the video games, and you shouldn't gimp or leave out interesting narrative or multidimensional characters because there are books out there.