Really good question...

The Saffir-Simpson scale was initially developed in the late 60s by Hebert Saffir, a civil engineer who wanted to be able to quantify the damages that various magnitudes of wind speeds from a hurricane could inflict upon the coast. Thus, while it may not be explicit, I would imagine the scale -- which has remained unchanged since the early 70s -- was written with late 60s building codes in place.

The initial emphasis was on the wind speed portion of the scale, though storm surge and various subjective damage estimates have been categorized along with the various wind speeds since then. Sometimes, you'll see pressure lumped in there too. (That brings up the whole debate about the best measure of a hurricane's intensity, pressure vs. wind speed, which I won't rehash in great detail now. Pressure is generally a better measure of the intensity, as when combined with the pressure of the environment of the storm, you can get a feel for what the wind is going to do via their direct relationship. However, it's the wind that causes the damage...in effect, one affects the other and vice versa. But I digress.) As we all know, however, two category 4 hurricanes, one moving fast and of a compact size and another moving slowly and of a larger size, are going to result in vastly different damage profiles upon landfall. How do you make up the difference? It's tough to do with any one scale, and that is why the Saffir-Simpson scale is necessarily broad. It's also a testament to our wave modellers and tropical forecasters in how they generally get the impacts of any given storm right.

Personally, my viewpoint is that the Saffir-Simpson scale is borad and indistinct enough to cover all possibilities within its categories. Motion, size, intensity, and the environment all play a role in what any given storm will do, meaning two storms of equal wind speed may have vastly different damage profiles. My feeling is that assuming equal wind speeds between two storms, despite these aforementioned differences, the overall damage patterns are going to be similar in magnitude -- minimal, moderate, extensive, extreme, or catastrophic for categories 1-5 respectively -- between the two storms.

In essence, from this viewpoint, it becomes an education exercise to the public as to what the scale really means and how best to interpret what a given storm will do to your region. This is much like the debate about the NHC maps that existed at the start of this year. While building codes are stricter today than they were in the past -- anything built to 1960s code along the coast isn't likely to make it through a category 2 hurricane, IMO -- the sheer increase in population & density along our coastlines makes up for the difference. While all homes won't be leveled, as they may have been in the 60s, many homes will suffer at least some damage, sort of negating the difference in building codes. Thus, I don't think this argues for the scale to be redesigned, just argues for a better understanding of a storm's impacts as it relates to the scale....perhaps clarification of various points of the scale, but not a redesign.

As an aside, with very intense hurricanes, trained observers will occasionally go in and survey the damage to help estimate the storm's intensity at landfall, but to a large degree, that estimation is still done largely with numerical data. For instance, the reanalysis of Andrew as a cat. 5 storm included both aspects, but relied heavily on observational data from radar, dropsondes, land-based anemometers, and similar stations. The reason for this is that it is tough to distinguish on a very fine scale between damage -- and in a lowly-populated area, you can get a vast underrepresentation of the damage due to a lack of structures to go off of. ith tornadoes, each category has a much wider expanse of winds, making categorization easier on a subjective basis. This debate was brought up with Charley a while back and is still valid here. There's no real answer I'm getting at here, just providing my viewpoint, but whether or not the Saffir-Simpson scale needs revising...hurricane intensity is generally an objective exercise and will likely remain so for the indeterminable future.

Just my two cents...but definitely a thought-provoking question!