However, Atlantic temperatures were warmer than normal in parts of Sandy's path (mostly towards the end). Just because Sandy had no hurricane force winds at landfall doesn't mean Sandy was weak. Sandy had more wind energy than most stronger hurricanes, but spread over a large area which can inflict more surge damage in the right (unlucky) circumstances.
Comparing small powerful hurricanes to Sandy is illustrative. Charley which hit Florida in 2004 was category 4 but very small. It's central pressure was only a bit lower than Sandy's (941 vs 948). It's winds were 140-150 mph and that caused a surge as much as 10 feet in a very small area. Sandy's surge would have been smaller but just happened to funnel into the NYC area at high tide. The 1821 hurricane hit NYC with a smaller surge but came at low tide so the surge would have been higher than Sandy's.
In short, the effects like surges are nothing new and we can't pretend they don't exist, "climate change" or not. But global warming, such as it is, has some effects: the current inch per decade sea level rise in places like NYC and the warmer Atlantic temperatures (although part of that warmth is AMO, a cycle). So we should set aside some money and build some surge barriers (e.g. Verrazano Narrows) and elevate the substations, buy some more pumps, etc.