Lessons learned and people "got gone". (rant)
First off, I wasn't there anywhere, so this is from talking to folks at two conferences, and etc's revolving around Guard and being EMT-A in Lincoln, Nebraska when Grand Island got urban renewal from a twister in 1981.
A big part of the Katrina debacle was due to FEMA beng used as a political sop appointment by the president for an unqualified political crony ("Brownie"), and even then it might have worked except managemernt was very top down, so the buck stopped before it started.
Another big part was that local emergency/disaster plans were apparently not workable, based on individuals and not offices (i.e., "Charlie will unlock the bus compound" should have been "The first disaster preparedness representative on scene will unlock the bus compound", etc.).
Third, many local people reportedly voted down levee improvements and otherwise were not interested in preparing for "the big one".
Fourth, this was a monumental disaster which sorely impacted the responders in the affected area, proving the axiom that disaster response is "reverse centripedal" (comes in from outside).
Fifth, welcome to what the military terms "hurry up and wait".
I am not seeing public reports with serious bottom-up planning responses. Communities need to take the reins, as do counties and states, and especially in the aspect of forging mutual aid agreements and FOU's with private suppliers of transport, water, commo, etc.
Many "SUV's" who show up are going to be undisciplined, under-trained, and in need of logistic support, so they will need babysitting/mentoring untilk they are settled. If local authorities come up with a way to fast-track authorization and can provide the framework to use SUV's, then good.
Stop depending upon FEMA.