NJ is a top 10 GF team over the last 2 years. Now before everybody points to last season, they were 2 goals away from being in the top 10. I don't think the issue is adding more snipers. I like Robertson, but Hischier is the matchup player for them. He's their defensive center. There is a enormous hole without him. Dallas on the other hand still has Hintz and Duchene down the middle so it doesn't make much sense for them to entertain this either.
This is bad for both teams involved and not one of those "Must be good if everybody hates it" trade.