I've seen the Islanders make a lot of big acquisitions over the years that were immediately, and transparently awful fits. The ones that come to mind are Trevor Linden, Wendel Clark, and Kirk Muller. (Yashin for all that happened with him as not as bad as those three).
Horvat is not setting the world on fire (tbh he's been snakebitten), but he's an excellent fit for their style of play. He's such a patient player. For all NYI lack that dynamic element (I won't deny NYI lack dynamic play from their skaters), it's like they have a captain on the ice at all times.
I don't know what's going to happen, and I am neither predicting success (nor jinxing NYI), but I really hope they make the playoffs for Anders Lee's sake. It's pretty special, imo, for a big guy like him to have worked himself back from a torn ACL the way he has. The guy works so hard.