The NYC has been a massive thing for NZ league. So many of the Warriors U20's have come from Union, guys who previously wouldn't have made the switch because the pathway wasn't there. That's the biggest thing that the NYC has given the Warriors, a genuine pathway for league players.
As for the Warriors dominating the comp, it's bound to happen. Can't remember where it was (maybe this forum somewhere) but there was a comparison between the Warriors players and the players from the opposition (Raiders were used I think). Turned out that there was nothing between the forward packs in terms of weight and height, but the backs were on average 9-10kgs lighter compared to the Warriors. That extra size across the park is what sets the Warriors NYC apart.