I'm late to this party, or should we call it a wake? Koch isn't going anywhere, so I'll put in my two cents; I lived in NYC during the last year of Koch, through all of Dinkins, Giuliani, and the first term of Bloomberg.
From a completely uneducated, self-reliant perspective,
Koch was a character, he was perfectly comfortable in his position, but the city was dangerous and dirty. I remember being rather nervous to ride subways off peak hours, and I had to do it. It was filthy, crazy people were walking around the city; it stunk.
Dinkins was a poor mayor. It's not his fault that the race riots lit up in Williamsburg, but his actions didn't help. He will be remembered as history's footnote. He just died, I think.
Rudy's administration turned things around, in my version. Crime dropped, international tourism picked up, the city cleaned up. I do miss the peep shows in Time Square as much as the next guy, but that's the price to pay for not having been knifed on a subway.
Bloomberg bought his mayorship three times. New York is not the city I used to love any more. The whole thing is just not what New York was to me, and to many others. It's hard to describe...just can't relate to it any more.
This is a good film, The Bonfire of the Vanities. It illustrates some of New York during the Koch years. I should read the book.