Research shows that only one thread dedicated to Marine Park exists on GCA, and it was 6 years ago, and not very extensive. A lot has changed since then.
Outside of Bethpage, Marine Park is the course I've played most in my life. I absolutely love it, and have never been bored by it. Sure, it seems like it's a bit of a nothing burger from the tee, but the greens are so bold, with so much contour, that on most holes it absolutely does matter where you place your tee shot (though the renovation and reduction of a few greenside bunkers in recent years has made that less true).
When it comes to inexpensive municipal golf courses on somewhat nondescript pieces of land, I love the Marine Park formula, where you are allowed some room to spray off the tee, but the greens provide a thrill and a difficult two-putt on nearly all of them. And it's not like the terrain is dead flat. On most holes the land has slight tumbles and rolls. Outside of the trip up and back down the hill, I would say Nairn reminds me a lot of Marine Park in the questions it asks and the challenges it presents.
They've done a lot of work at Marine Park in the last 5-6 years, improving the conditioning and aesthetics, and they should be proud. It's still a 5+ hour round, but that's life. While I absolutely loathe slow play, I'm so accustomed to the length of a round in the NYC area that I've almost gotten to the point where any round that doesn't keep me on the course for at least 4.5 hours instinctively feels like some sort of rip off.
There's a lot more they could do, of course. They could add more fairway features that require more strategy off the tee. But if the money is not available for that, or if the worry is that the rounds will stretch consistently beyond 6 hours, then I can understand why they do not. As it stands, faced with their history and unique set of circumstances, I think Marine Park is about as good as could be hoped for. I'll take relatively bland fairways and mega-exciting greens over the opposite any day of the week. Put simply, I am beyond thankful that this course exists so close to my home.