Are you familiar with Rita and Ike?...both stronger than Sandy.
Don't mistake CAT, based on windspeed in the tropical winds core, with total storm strength.
Sandy was a large hurricane with a lot of water that formed in a few hours just South of Jamaica. It ran into and was absorbed by a large Nor'Easter that was in turn part of a front that extended from the tropics to the arctic! This one storm center was 1000 miles wide. Try pi r squared for territorial extant. It was UNIQUE.
Ike and Rita had nowhere near the destructive force of Sandy ~ which is still spinning BTW!