It's really hard to judge these days. It seems like the more we go on, the older stuff kind of gets pushed into a bin labeled "The Interpretation Bin." Events keep changing and being retconned, and as we go along, we're just kind of dumped with, "Well this might have happened, but events are sketchy." Take the fissure of TFoR and Halo:Reach.

There was a popular theory going around some time ago, that Halo:Reach was actually ONI propaganda, heavily twisted to fit their own ends. And, if my memory is right, maybe even the data drops from 343 confirmed it, or helped spread the theory around. So the novel got shoved out of the way into the garbage bin, and then the game itself did as well, with both being left up to the interpretation of the fans.