On the positive side, I think the defense is set for the next couple years. With the development of DPetey and Willander, there's a good chance it becomes the best unit in the league at some point. In Hughes' contract year, they could have 5 top 4 dmen on the team, with one of them being the best in the world. There's also some longevity attached to it given everyone's age, and that dmen typically stay at the apex of their game longer than forwards.
Given that, I'd hope the coaching staff starts to do more to activate the blueline on the rush. With Hronek & Hughes showing they can run their own pairs, you have one guy on each who has good offensive instincts if the team can find enough forwards with the skill to carry the puck into the zone instead of dumping it in every time.
They need an RW1 and C2 at minimum this off-season, with the idea that both can play off the rush and that the RW1 can be an excellent contributor to PP1. One of the first places I'd look at is if the Islanders are willing to part with Barzal after an injury riddled year, especially if Lou is fired/they decide to go full rebuild. C2 is a bit of a tougher challenge to acquire, and how good said player needs to be really depends on how well Chytil plays down the stretch.