As a Canucks fan, this looks like the sort of deal that New Jersey would only take if they figured the future is now and anything after that will take care of itself. As a Canucks fan we've seen a lot of that king of thinking the past eight years.
It would be virtually certain that New Jersey would be better in 2022-2023 for making this deal. It would be almost as certain that New Jersey would be worse four years from now and for some time after that for making this trade. The big question would be how long it would take for the trade to be negative from a NJ perspective.
I don't think New Jersey is in a go-for-it-right-now-while-the-window-is-open situation. That being the case, I don't think this trade makes any sense for them.
I also don't think that Vancouver is in a go-for-it-right-now-while-the-window-is-open situation, so would look at the proposal in term of future value and think that it gives the Canucks good value for what they would give up. Like most Vancouver fans I don't want to trade Demko, but I don't consider that any player on the team is untouchable, given a good enough return.