I don't know how the absence of tragedy related scams degraded into a "brilliant" political analysis of the first idiot and his pin head challenger, but the biggest difference is that New Orleans sits below sea level. There are levee's surrounding it and there are massive sump pumps under the city that run pretty much 24/7. So when the city floods, there's a fairly probability that the power feeding those pumps stops. A fair portion of NYC sits a fair piece above sea level and it's on bedrock.
While Sandy was a big storm, statistically, the storms that move through the gulf of mexico are much more powerful and bring a much higher storm surge along with them. So one would figure the municiple government of New Orleans would have learned from neighboring gulf states.
While Bush was another poor example of American leadership, he didn't go to New Orleans simply because he knew the Secret Service would attempt to rob every available first responder from the job of actually helping for additonal security detail support. The current administration wanted to come to NYC to survey the damage, but the mayor at least had sense graciously decline the visit request. Instead he toured New Jersey with their governor.
Perhaps the biggest difference is that instead of the examples set by the Mayor of New Orleans and the Governor of Louisiana, the Mayor of NYC remained in the city and the necessary authorities made sure that the City's support infrastructure didn't degrade. When the management of both New Orleans and Louisiana bailed to save their own skins, even when they had every convienance at their disposal, the city and state fell into a state of anarchy.
Finally, even with all the warnings to evacuate, most of the people down in New Orleans stayed put. Being unable to live off the land like the cajun folk and completely unprepared, I'm really quite surprised there weren't more tragedies. Personally I hold the mayor of New Orleans and governor of Louisania completely responsible because of their utter lack of leadership.