I flew in and out of LGA airport 2 times in my life so far. Last year, my flight was delayed 4 hours because of wind shear. My flight from Toronto was held due to the backlog. It's really a go-go airport, as soon as an aircraft lands, the holding aircraft is told to taxi into position and hold, takeoff immediately and let the inbound aircraft land. Any delay causes more of a ripple effect than most airports because the ATC is also restricted to the airspace they can utilize for another runway.
I hope in the new terminal they can utilize the space and improve efficiency but IMO they've reached capacity in terms of aircraft movement.