If people believe Boeing could be covering something up, they're filing to make sure it can't get rid of anything - once you know litigation is coming, it's a lot easier to get in trouble for getting rid of anything possibly related. There are money hungry lawyers involved too, I'm sure, but did someone say the person who filed was the father of a passenger who had aviation knowledge or was an attorney? I remember reading he had some sort of related expertise, so he would know the importance of preserving Boeing's records.
The poster who talked about the hypoxia issue reminded me that I just watched one of those Air Crash shows, and during the Vietnam war a military jet hit a passenger jet in CA. 2 pilots in a fighter jet that had oxygen issues - they flew low the whole way to avoid hypoxia, which isn't dangerous (not sure about the gliding issues - I think jets have less of an issue with that), at the direction of the military, to get it fixed. But, at the time, military and ATC had no communication with each other, and the jet was flying right into a major area for flights landing at LAX. So ATC doesn't know it's flying low at an extremely high rate of speed, the radar couldn't catch it because the radar was older and the plane was too low, and the planes collide. One pilot survived by ejecting - every other person died. The pilots could have avoided and tried, but it happened so fast and they were practicing flying without looking, which is a needed military skill. The pilots of the passenger plane had little training in looking ahead of them, and just relied on the electronics, and it turned out the window had a divider that blocked their view anyway.
It happened so fast that ATC had no idea where the plane had gone until it called the military and found out it was missing a jet.
Needless to say, after that, ATC and the military started communicating. But this was not that long ago, in the U.S., even given the concerns of the military.