I agree that the Saffir-Simpson Scale is limited in usefulness. It was created in 1971 to communicate the threat of tropical cyclones in an easy way that the public could understand, but we've learned way more about tropical cyclones since that time. Flooding and storm surge make up 90% of all hurricane deaths, but people get caught up on the winds so much that they neglect this crucial fact. The reality is that every landfall of a tropical cyclone is unique due to size, structure, movement, atmospheric conditions aloft, sea surface temperatures, winds, coastline geography, and so much more. I could imagine creating four separate risk scales for flooding, storm surge, tornadoes, and winds. Unfortunately, they would all be highly subjective as you wouldn't know what to put as low, medium, or high risk due to all the complex factors I mentioned above. Thus, you can't quantify the risk of any landfall in one nice scale with any reliability.
Ultimately, education is the best way to deal with this problem rather than creating risk scales. The public's lack of caring about weather and not wanting to understand its complexity has to be changed dramatically, or we'll continue to see deaths due to people not knowing what to do in warnings. The media and the NHC have been trying to educate the public for years. There are tons of books, pamphlets, and shows that teach you about the weather. The NWS local offices issue warnings that tell you the threats and provide call-to-action statements that tell you what to do, but it's clear that many people still don't read them. If people aren't willing to learn, then there's sadly nothing we can do other than use Cuba's tactic of brute force.
Anyway, Isaac has been downgraded to a tropical storm with winds of 70 mph, but it's going to be another long night in New Orleans.
