The problem with hurricanes, is that there are SO many variables at play, that that determine what the damage caused will be. A hurricane, is a hurricane. They should ALL be respected. Getting lucky a few times, makes people complacent.
The categories are reflective of the storms power. But. Speed of the storm, rainfall, storm surge, and SO many other things play a role. A small,slow storm with lots of rain, can be catastrophic, if the areas it hits are below sea level, and / have been saturated with seasonal rainfall before the storm even hits.
I guess I would almost say that the category, just tells you that a bad flooding event is coming, and how the weather will be on top of the flood water.
The flooding, and storm surge do most of the damage.
The storms are generally divided into quadrants. The northeast is by far the most powerful. So. Where the eye makes landfall, is a MASSIVE factor in damage.
As far as revamping the scale goes, I am OK with how it is. However, we have had storms that may point to a pattern of eventually requiring a sixth category.