I can foresee that they would have a lot of "grass" growing within a week! Conversely, make a good place for those non-existing 'homeless' to hang out.

Well makes a improvement over the dumping at sea that was illegal all over the world for 10 years before US stopped to.
Well they can use the stuff to make bio-gas, don't even have to invade any one for it, so its a win win for every one. But they expect a New Yorker to sort there garbage? That is whats needed to make things good quality dirt that can be used.

Take the stinkiest crap you can get your hands on, put it all in one place, and ... turn it into a public space?
This idea totally stinks.

Well, since it's a bit off shore, the stinky is nimby, and the flies have open skies...
But seriously, organic waste is substantial, although since it will have to be trucked off again after it has decomposed, it really isn't much of a solution. And New Yorkers would have to get committed to the program too.
Conversely, building park space on the river for such a densely populated city is a worthy consideration, as long as it can be well-managed and doesn't take away too much dock space.

One flood or thirty years of salty corrosion later and we'll be figuring out how to stop it from leaking into the surrounding water... smart.

Whoever came up with this idea has never been to a composting plant. In one word: odour.

So did I miss where all the compost then goes to on those trains and barges?

Well these look really lovely - only problem is have they designed them as 'floating' with floating road access too so they wouldn't just 'drown' if the seas rise ? - have to consider that for everything nowadays - oh wait - if they did that then these would make great 'escape islands' as and when the sea level did suddenly get high ! I could see NY'ers camping on the top if that happened (:>)

That is a great idea. Birds and rats will have their own private island vacation resort!

When its all full, turn it into a football stadium.