Sandy was only one part of a three part weather event.
Three major weather systems collided: a southern late season hurricane that was very big a high altitude Canadian jet stream that barreled in from the north and a winter snow storm that approached from the west. A relatively strong noreaster would have resulted if Sandy had not merged with these other systems.
When Sandy combined with the other storms it became a super storm.
Sandys immense size also comes into play. The peak diameter of storm force winds with Irene was 460 miles, for Katrina it was 435 miles. These are very large distances but only half as big as Sandy at 943 miles. This almost thousand mile wide storm had the second most kinetic energy of any storm measured and it struck a densely populated area.
It also has to be noted that the super storm hit at high tide, during a full moon. Results would have been much different if Sandy had hit a barren coastline in North Carolina or Texas.
“barren coastline in North Carolina or Texas.”
I see that you have never been to either state.