From what I’ve seen & heard about Staten Island, I get the impression that it’s much more suburban than any other borough of NYC. Actually, if you look at a map, it would make more sense for Staten Island to be part of New Jersey than anywhere in New York.
I think the proposal to unicorporate parts of Detroit has fizzled out. There are plans to clear out neighborhoods that are mostly abandoned, but these neighborhoods don’t form a contiguous block of territory which would lend itself to unincorporation.