Singapore does some of these things, sure, but not everything is great about the way they end up doing it. Sprawl is impossible in Singapore, but usable sprawl is a special strength of the United States. I think that if you tried to do Singapore again, you'd be missing out on an opportunity for people to live in houses (which most people greatly prefer to apartments) and mixed-use low-rises (the hallmark of a beautiful, lively city) still without missing out on sub-half-hour commutes.
Singapore also has the problem of being tyrannical in basically every way except the economic, I figure it should be legal to walk around nude in your own house, and also legal to chew gum.