I'll throw some comments your way
First, I wonder if you've taken a look at the 'Big City USA' ideas & plans that were drawn up for Disneyland CA a few decades ago that would have gone behind Fantasyland, and later inspired the American Waterfront at Tokyo DisneySeas. Like yours, it connected to Fantasyland, and also contained a big Broadway theater. Their's also had an old fashioned, Coney Island style amusement park (which would later inspire the amusement park for Disney's America, and later DCA's Paradise Pier).
It's great that you've suggested Hong Kong or Shanghai for this land. As we don't know what Shanghai will look like, I'll run with this being planned for Hong Kong, where it would fit in well behind Fantasyland, possibly also connecting with Toy Story Land to stop it being a deadend. In this case, I wonder what should be done with the Golden Mickey's show, which is very Broadway styled, but located in Fantasyland.
First I'll say what I like;
Enchanted: The Enchanted attraction would work brilliantly as a transition between Fantasyland and the New York area (New York streets on one side of the showbuilding, Giselle's castle on the other, perhaps?). An Enchanted attraction would also be a good addition to the park.
Tower of Terror: A New York land is a great way of getting the Tower of Terror into a Magic Kingdom style park, so I really think this is a great idea. Losing the Twilight Zone theme is also wise, considering the source material probably isn't well known in Hong Kong or Shanghai.
New York Hotel: Another brilliant inclusion. It worked in Paris, and it will surely work in Hong Kong or Shanghai - selling one of the best aspects of America, the Big Apple. Having it in the park also allows for the 'sleep in the park' bit of magic, and it could even have it's own guest only entrance directly into the park, like at the Grand Californian.
Broadway Theatre: Definately! A big, grand show location, and the choice of Beauty and the Beast is a great choice. I imagine it to be on the scale and scope of Aladdin: A Musical Spectacular at DCA.
Now, my criticisms;
Spiderman: I'm one of those people who's rather skeptical about the inclusion of the Marvel characters in a Magic Kingdom style park. Hollywood Studios? California Adventure? Fair enough! But Magic Kingdom park... I'm not convinced. I think it *could* be pulled off, but I really think you'd need to go for a retro style Spiderman, kind of working him into the Golden Age of comic books. This could of course be expanded to the rest of the Marvel superheroes. I can definately imagine a small, 1930's style newstand on the street, but a multistorey comic book shop... not so much.
Muppets: Here, I'm not entirely convinced with the draw the Muppets would have in Hong Kong or Shanghai, and I'm not sure it's realistic that an entirely new Muppet 3D film would be greenlit, especially one that narrows down its 'clone-ability' to just New York. Personally, I wouldn't include this attraction, but I can understand why you have. I don't have my own answer to this figured out, but would MuppetVision 3D work here?
Ballroom Dinner Show: This I'm not sure about, because I'm not entirely convinced of the theme. I understand the need to a fine dining location, and definately think it's appropriate to the land, but, when there's already an Enchanted attraction, and the dining room itself isn't very unique (okay, the fight would be, but I still don't quite think it 'gels'), I think a different restaurant would be more effective.
New York Hotel: I complimented it before, but I'm coming back to it critically because I'm not convinced about the 'three wings' idea you included - Muppets, Broadway, and Hotel Hightower. WAIT! Scratch that, thinking about it I'm liking the idea. A Broadway wing is a great idea, and the Hightower wing is also a great way of fulfilling the fantasies of everyone who's actually wanted to sleep in the Twilight Zone Tower of Terror. My only problem is the Muppet part. Theming each room to an individual Muppet would create a headache with all the people requesting the lone Kermit or Miss Piggy room, and the chaotic nature of a Muppet hotel doesn't really fit with the elegent nature of the other two wings. If this was built, it would no doubt be a deluxe resort in Disney's eyes (park views, private entrance), and for those resorts, Disney likes to make things classy to attract the richest guests, while saving the more chaotic hotel designs for economy resorts. Personally, I think another theme for the third wing would work much better.
The biggest problem I think is not with the location but with time period, as it contains a number of disparate elements - Hotel Hightower being in the 1930s, whilst Enchanted and the Muppets are contemporary, and Spiderman depends on which styling you go with (retro or modern). My personal choice would be to go with just a 1930s style New York, which I think would create a nostalgic magic that Disney thrives on, but I realise this would be hard to stick with when an Enchanted attraction should be included. My suggestion therefore, would be to do what they did with Frontierland in the Magic Kingdom and have a moving timeline as you go through the land. Have one side be modern (with Enchanted, Muppets perhaps and so on), have the other side be 1930's (with the Tower of Terror and the Broadway Theatre), and blend them together as you walk across the land. This stops the contradicting elements, but also allows everything to be included.
I like where you're going with it, and there's a bunch of cool things that could be included. A burst fire hydrant gushing water into the street, 'newsies' style newstands, puttering motorcars. The steam train could be elevated up like the elevated railways that thread through New York, adding some great kineticism. Shops and counter service food locations could be themed to automats, corner diners, pizza restaurants, cafeterias, delicatessens, --- even a laundromat!
There's a ride called 'Cops and Robbers' that was designed for the American Waterfront but never built that would fit great. It was a dueling wild mouse coaster, all built inside, with one track having police themed cars, and the other side having getaway cars, racing eachother through the busy streets of New York. Or how about including a gangster themed attraction, perhaps similar to the D*** Tracy's Crimestoppers ride that Disney developed. You could have a Speakeasy hidden somewhere in the land with jazz music and dining. Perhaps consider Disney's idea for a Coney Island style area? It could be a good transition into Toy Story Land at Hong Kong, and could work with some good period theming, and the inclusion of one of a kind classic fairground attractions. As a replacement for the Ballroom Dinner Show, could I suggest something like 'Dining in New York', a restaurant developed for Festival Disney (now the Disney Village) at Disneyland Paris. Imagine an indoor restaurant underneith a starlit sky, just like the Blue Bayou, but themed to be the rooftops of New York, with skyscrapers and the Statue of Liberty on the horizon; guests dining by candlelight next to the iconic rooftop watertowers of New York.
Oh! And one more thing, I'm not sure about the name 'New York New York Land'. It's overly complicated I think, and would just as effectively work as 'New York Land', or you could go with Disney's idea and use 'Big City USA', which I'm personally really fond of - I think it makes a nice parallel with Main Street USA. Save the 'New York New York' phrase for a shop or something similar!
Hope this is of some use to you!