I compared NW and GH3, which should have very little differences between one another, but to me one felt like a piano and the other one didn't. I think its all up to the person playing.
Yes, but I think that "feels (exactly) like a real piano" is a slightly different criterion from "feels nice and playable", which is more important to me. For weight reasons alone I think it's clear that e.g. a stage piano will always fall a little short in terms of the first criterion, but can still be wonderful in terms of the second.
And of course acoustics aren't all alike. So that comparison is always a little difficult, because it depends so much on what people are used to. There are those that claim a Casio action feels "exactly" like their acoustic, and there are those that make the same statement for Yamaha actions. And to me the differences between Casio and Yamaha are far grater than between the different Yamaha actions, although like I said I agree that e.g. the 223 is pretty great. Perhaps NW is even better still. But I don't find it difficult to adjust to any of the Yamaha actions, even a good Roland doesn't feel all that different to me except for its shallowness (are they trying to emulate a fortepiano?). Casio is another matter...
Besides, what exactly is the action on the 223? Is it a separate development? I can't seem to find details on that. It just says "premium GHE", but where is this supposed to fit in the spectrum of GHE/GH3/NW?