It’s my understanding that “category 5” means “total destruction”, which is why this hasn’t been done in the past. However if it helps to get the point across about climate change, it would be helpful for marketing purposes.
Sorry but that reason for a change feels very coercive. If cat 5 is intended to be total destruction, meaning that anything above the lower bounds for a cat 5 is indistinguishable, there should be no 6.