There is no top end to a Cat 5 hurricane classification, so no need for a higher rating.
This first part of that statement is factually true; the second part is your opinion. If hurricanes start becoming 4x as powerful, the category 5 is still applicable, but less useful. What Gore said was correct: there are scientists considering adding a category 6 to differentiate amongst the strongest of hurricanes.
To be awake is to be alive. -- Henry David Thoreau, in "Walden"