Firstly, SW NE did get a good deal of snow from that Jan 2016 event, and the Dec 1997 was very prolific north of Boston, regardless of what took place in your back yard. Additionally, those three la nina events were barely over the strong threshold. Secondly, you can't count one season three times. 2/3 of those la nina seasons featured no major SNE events...all three of those super el nino seasons did.
Sorry, but you're wrong. The prominent STJ in stronger el nino seasons, while not ideal for this region, is better for the prospects of major winter storm than a strong la nina regime. Additionally, el nino is more highly correlated with neg NAO, than la nina, which is another reason why it is more beneficial.