I want Duchene to stay! What a great addition.
IMO the addition of him and Dzingel, not just counting their contribution, has another effect - it brings fresh energy and you can see they have loads of it (since they played in a non-playoff team for most of the season). Guys who have been on the team for the whole year don't seem to be as rested and seem lest energetic then them. You can see Panarin and Dubois not being 100%.
Remember last year vs the Caps? The guys were tired and the 2 wins we got were because of skilled plays which allowed us to win the game and after that, the Caps kept on pressuring us and they had way more gas in the tank left compared to us.
Adding this fresh blood really was beneficial.