It's make or break year for his pay day, for sure. If he is going to command 8.5/9 million, he'll have to produce. The cap is going to go up eventually and you don't want to lose a player like Barzal, but you can't just hand out contracts that high while receiving production that doesn't justify it. There's always the losing the player vs being slightly overpaid argument, but you need better production from him to justify it.
Islanders should be different. I think many non-Islanders fans are in agreement with Islanders fans that he offense will be better utilized with more freedom, whether that takes a slight hit on the backend team defense or not, it probably needs to happen.