The reason for the switch is S&W isn't making metal framed pistols anymore, 5946 included. The NYPD buys guns by the hundreds if not thousands. If that size order isn't enough to persuade the factory to produce a run I'm thinking they are cashing out on the 3rd Gens period.

And I'm willing to bet the NYPD will specify some rediculous trigger and ruin the gun, just like they did with the Dept issued Glocks and Sigs. The 5946 met Dept regs right out of the box so it never got messed with and got to remain in all its S&W goodness.