I just remember the blackout when Koch was mayor. He did Zero and let whole neighborhoods get looted. Can't picture that happening under Rudy. When the Rodney King verdict came down, NY's finest were ready and stopped the rioters in their tracks unlike many other places. As far as setting things up for Rudy, I don't see it. Koch set up the City for the disaster of the Dinkins Admin, which set things up for Rudy.
Rudy was a prosecuter, so he's gonna be the law and order mayor. Koch was pretty much the anti-machine, machine mayor.
Most of the deals involving Times Square were cut under Koch. The fashion industry stuff, like fashion week, etc. which brings in a couple hundred million to the city, was under Koch. A lot of development downtown. Closing the SROs, etc. were all under Koch.
So, all this stuff is in place when Rudy comes in, but the city is in a recession. Property values falling, crack running wild. Murder rate above 2,000. And Rudy hires/promotes a bunch of genius cops -- Bratton, Timmony (sp?), Jack Maple, Kelly, etc. They start enforcing quality of life laws, put computers in cars, put computers in 1PP. etc. etc.
To some degree crack is a "self cleaning oven" and crime drops, but to a larger degree, all the new programs work as the deals that Koch cut come to fruition.