Stepwilk: Your observation is correct. I have been in and out of the city too - in both helicopters and fixed wing - and can say, that if everybody observes the rules stated by you, operations are safe.
I have actually observed/encountered many more close calls on uncontrolled airfields than in the Hudson River corridor.
Calling for more regulation because of one tragic accident is a knee-jerk reaction usually proposed by politicians/media, not by professionals.
See and avoid works pretty good in my experience. I agree that over a populated area its hard to spot traffic below the horizon, but over the hudson you have mostly water in the backdrop, so it is pretty easy to spot traffic. Rules are in place already and observed by almost everybody: right "lane" traffic, if you depart a heliport give way to traffic - it's actually like road traffic and you wouldn't question the worldwide traffic rules just because one truck driver rear-ended another because he was distracted or his brakes failed.