I feel the scale shouldn't be based on wind alone and adding a cat 6 level is kind of silly. Rating categories is a meteorological thing right now, it should be based on impacts.
Hurricanes really should be ranked on threat level to population from all impacts. Take into account wind, storm surge and rainfall. The article calls Hurricane Katrina a category 5. It was a category 3 at landfall but due to it's size, fetch and the area it impacted it ended up being one of the worst disasters in US history. Category 3 does not represent the threat, only the wind speed.
Same goes for Tropical Storms Allison and Imelda or the unnamed tropical low that created the 2016 LA flooding or Hurricane Florence (cat 1). Those were closer to a cat 3-4 based on impact to property than some random tropical storm and easily posed a much bigger threat than Hurricane Patricia did as the strongest hurricane ever recorded. Patricia was fast moving and tiny. The hurricane force winds only extended out about 15 miles from the center, it was moving quickly, hit an unpopulated area with little surge impact. The costliest disaster in US history was Sandy, it's classification was a post tropical storm and no category assigned. Sandy was the equivalent to a category 1 hurricane, the damage was greater than any category 5 ever seen. However, that damage was spread over such a massive area it would be a category 3-4 based on impact to life and property.
On the same level, some hurricanes should be downgraded based on impacts even though the wind speeds were higher.
I kind of like the way California rates the atmospheric river events. They keep it really simple. Minor, moderate, major and extreme impacts. They assign an impact level to rainfall, mountain snow, coastal impacts from waves and then wind. It identifies each threat and communicates to the public what should be the biggest concern.
I speak to so many survivors that simply are not prepared to deal with the impacts because it was just a tropical storm or a cat 1.