Manhattan might have more mentally ill homeless people than before but as someone who grew up in Brooklyn and Queens things are way safer than they used to be, mostly thanks to gentrification (mostly due to Bloomberg rezoning the Brooklyn / Queens waterfronts) and not any of the recent mayors.
The gentrifying parts of Brooklyn + Queens (and the Bronx!) have gotten better—-no thanks to tweedledee and tweedledumb. But the parts that were already middle class have gotten worse, just like Manhattan.