Probably the most important lessons (IMHO):
1. In a major disaster, you cannot rely on any government, volunteer or commercial services for at least a week.
2. It is an absolute necessity for politicians, at all levels, to seek out compentent emergency managers and then listen to them.
3. Since September 11, 2001, the U.S. Fed Gov has been total immersed in the reponse to another large scale terrorist attack and disaster prepardiness has been treated almost as an afterthought. The U.S. "Department of Homeland Security" needs to be realigned. It should become the "Department of Emergency Prepardiness" wiith an "Office of Homeland Security" and an "Office of Disaster Prepardiness". There are many areas that overlap, but the basic concepts behind both are very different. Keeping them in the same department will allow them to work together in the overlapping areas without too much institutional conflict.
4. "Turf", bearuracy and red-tape. There are so many examples where efforts to help people were thwarted by this crap it's sickening.
Oh well, I was going to try to be brief...
Stay Safe,
Jim