Must be look at the big picture.
The last sentence says it all. "Those laws were put in place to reduce overcrowding and stress on surrounding infrastructure, something that Singapore was forced to address when shoebox units took off there."
I hope the zoning changes to allow these micro apartments also change parking requirements and a host of related codes that impact quality of life. Otherwise they will exasperate existing parking space shortages by adding dozens if not hundreds of cars to a neighborhood as more people a stuffed into a smaller area.
Unless the make the drastic change of prohibiting vehicle ownership to people living in these packed units. If they do that they had better make sure the housing is near adequate public transportation.
In the glory days of Hells Kitchen and thousands of similar neighborhoods across the nation you could cram lots of people in a small area because everyone walked. Everyone did not have cars, or going back farther, horses, to worry about.
And cars are just one aspect of the puzzle.
Can the sewer system handle the increase? Can they provide enough municipal water? Electricity? Have they planned space for additional/larger food stores to handle the population increase? The list goes on, but you get the point.
If not properly managed this could spiral out of control very quickly into an urban overcrowding nightmare.