High-rises separated by green space was the original vision of high-rise designers. But what developers and financiers heard was "more salable square footage in less footprint" and we ended up with what we have now.
I personally don't enjoy living in high-rises. If I had to design city, it'd be more like San Francisco: buildings 5-6 stories high, tops. Lots of walkspace, lots of trees, definitely a lot more greenways as you describe.
But I don't see the point of having all that greenspace if the majority of people will be 20+ stories away from it.
Population density is required to make all amenities to be within walking distance, and to make meaningful public transportation (one you can rely on). In your scheme, low density would mean one has to drive to see your friends or visit favorite caffe (hello traffic gridlock) or take a bus, which will take forever over longer distances and all the traffic light stops.
My concept is to build a city as a 10,000m square with building spaced out at 100m from each other in a grid for a total of 10,000 buildings, each one of 20 stories, 4 flats per story, each flat 12 meters to the side, three persons per flat. This way I could fit 2.4 million people in lavish 1400sqf condos in the city size of 10km to the side, and have the bus to cross the city in 10 minutes through underground tunnels with no traffic light stops.
Large population density creates huge opportunities for development of arts, as there is more audience and a bigger chance of there being enough supporters for a given new art thing in one place.
I personally don't enjoy living in high-rises. If I had to design city, it'd be more like San Francisco: buildings 5-6 stories high, tops. Lots of walkspace, lots of trees, definitely a lot more greenways as you describe.
But I don't see the point of having all that greenspace if the majority of people will be 20+ stories away from it.