NY (or Miami) triggers started out as expedient triggers designed at the request of the Miami Police Department, and the New York State Police. The original thinking was to avoid accidental discharges during an agency's transition from previously issued revolvers with their genuine double-action pull to Glock pistols with their pretensioned striker-fired actions.
You may remember the rash of ND/AD's that occurred among the nation's police departments during Glock's first decade in public service. Literally hundreds of police officers managed to either shoot themselves or a comrade. The NY/Miami trigger was Glock's (demanded) solution to this problem.
While Glock's, so-called, 'Safe-Action' trigger remains under constant pretension, the addition of an NY trigger spring provides a reasonable facsimile of an authentic double-action trigger pull. As things have turned out, many people (I'm not one of them.) prefer a Glock with an NY trigger installed. Massad Ayoob is, definitely among them. Apparently, any shooter who, either, prefers or is more accustomed to using a double-action trigger will like using Glock's NY trigger spring.
The point has already been made that fewer ND's or other handling mistakes occur when police pistols are strictly double-action, or single-action, but NOT both. It is, however, emphatically untrue that, 'As long as you keep your finger off a Glock's trigger you are safe from an accidental discharge. I WISH this were the case; but it is not. In the 8 years that I've been carrying a Glock, I've met plenty of other shooters who've, one way or another, screwed up with Glock's so-called, 'Safe Action' trigger.
During my own 50 + years of pistol shooting experience I've never found an acceptable alternative to the additional conscious step of pushing off a pistol's manually-applied user safety BEFORE firing. In everyday life the practicality of this concept becomes muddle, though. This is because with a true double-action revolver the straightforward 8 to 12 pound trigger pull is an acceptable alternative to the manually-applied safety on a semiautomatic pistol.
The confusion comes from the fact that double-action pistols are not operated by a pretensioned trigger mechanism; BUT, Glock pistols (and a few others) are. A pretensioned striker DOES make a significant difference in the inherent safety of a pistol. With a pretensioned striker, a pistol might, very well, seem to be, 'going off too easily'.
Now, is an NY/Miami trigger spring setup the answer to Glock's handling problems? No, not in my experience. This trigger mechanism remains popular, today, simply because there's a body of pistol shooters who prefer them. (I guess you know that Glock's NY trigger springs come in two different spring strengths: 8 and 11 pounds. 8 pound trigger springs are the most common.)
8 pound NY trigger springs are often paired with 4.5# connectors in order to produce overall trigger pull weights of 5.5 to 6.5 pounds. (The feeling of using a genuine double-action trigger is there; but so is Glock's usual pretensioned trigger pull.)
Now, quite honestly, I've never heard anyone who is genuinely familiar with a Glock refer to the trigger pull as, 'too light'. In the real world that just doesn't happen. Perhaps what you're referring to is that a Glock's standard pretensioned striker tends to fire too suddenly? If this is the situation, the solution is simple: Practice more and become more familiar with your pistol's trigger mechanism.
