SHIELD, even absent Iron Man, Thor and co, is an extraordinary organisation dealing with extraordinary threats in a fantastical universe. Gotham PD, without Batman and his gallery of villains, is just another police force in an ordinary city, albeit one with a particularly high crime level.
And let's face it, it's not like the depiction we saw in TDKR was a particularly realistic depiction of policing. Hundreds of cops living underground but looking remarkably well-fed and clean? Even with the outline Christopher
describes, I can't see this taking off. It would be too unheroic for the comic book crowd and is hardly going to compete with The Wire as a depiction of a gutsy police force dealing with organised crime. And, as Gaith
has intimated, we pretty much know how it's going to resolve.