I definitely think his game has dropped off a bit lately since being moved back to the kid line, points aside. Part of it is that line just being ineffective and getting stuck in their own zone too often, which is obviously not all on Kakko.
He is not getting much PP time and his 5v5 production has been lackluster despite getting the 4th most TOI among forwards 5v5. He is shooting <7% on the season, among the lowest of regular forwards (DiGi, Gauthier, Howden and Kravtsov are lower but all played less TOI than Kakko). As we all know, he needs to work on his shot. He also is only 7th among forwards in rush attempts / 60...this could be a product of his footspeed plus his linemates plus his usage (starts a lot of shifts in the o zone).
On the positive side, he has been good at winning the puck back when he doesn't have it (2nd at takeways / 60) and not giving it away when he does have it (3rd at giveaways / 60). He is also doing a really good job creating chances - 3rd in individual shot attempts / 60, 4th in individual scoring chances / 60, and 4th in individual high danger chances /60. This combines to give him the 3rd best individual expected goals / 60 on the team.
Hopefully another offseason can help him continue to work on his weaknesses. But to be honest I also question where his confidence is at. It is obvious how much time in the KHL being an key player for his team helped Kravtsov develop. I do wonder if Kakko is best served figuring these things out at the NHL level, but that ship has kind of sailed for the NYR.
Edit - At the end of the day he already looks like a player you are gonna want in your hockey team for a very long time. That can be relied on in key situations and fill a role on a contender. The question will be if he will ever score enough to become the star we all hope he can be.