We visited NYC for several days with my 2 year old last year. There are so many things to do that I'd have a hard time signing up for something extra.
If admission to things like the Met and the children's museum were included, sure. But, if the classes and places are inconvenient, then it might not be worth it.
I made this map when we visited for a few days:
https://drive.google.com/open?id=1sMTSpCBq1vDTQDT91xiJvDW97Uo&usp=sharing
So sad, I had to trash FAO Schwartz from the map.
