Though it sounds like a cliché at this point, I'll say it again: the city is the best character in Grand Theft Auto IV. It's not the most eye-assaultingly sumptuous environment ever created (In fact, it has this distinctly abstract quality in comparison with, say, Far Cry 2 or Crysis), but GTAIV doesn't trade in visual density, it trades in cultural density. Which is to say, it teems with the sort of details that make it feel like a place civilized people inhabit. There is TV, Radio and internet: all the things you need to fictionalize if you want to render the cultural life of a modern city. The brownstones might not be photorealistic, but they do look different from the ones on the previous block. This is progress.
Which brings me to Balzac. As a novelist, he's known for a few novels: Pere Goriot, Lost Illusions, Cousin Bette. But all these individual novels are just episodes in a ninety-five-work strong über-novel, which Balzac called La Comedie Humaine. (“The human comedy,” a callback to Dante's divine comedy-- which is now, implausibly, a video game) La Comedie Humaine is a panoramic satire of French (usually, Parisian) life during the restoration period. One of the basic conceits is that all of the characters in the comedie inhabit a common fiction: for example, the young and idealistic parvenu Eugene Rastignac appears in over a dozen novels. He's not always the main character-- sometimes he just makes a quick appearance-- but his persistence across the work gives the imagined world a feeling of coherence. Balzac saw each work as an opportunity to bring another perspective to bear on the phenomena that drove French society: money, sex, and status.
Now, let's be clear: Rockstar games is no Honoré de Balzac. Their preferred register is low satire, which means that your trenchant portrait of consumer society comes with a dick joke in it. However, Rockstar are men with credible ambitions when it comes to narrative. To play The Lost and the Damned is to be reminded that their dialogue and voice acting are professional grade. (It is unusual, even striking, to hear video game characters say the sorts of things that human beings say to each other, in the way that human beings say them to each other. On this front Rockstar is peerless.) Here is an outfit that is demonstrably capable of representing human interaction.
And this is why the episodic model exemplified by Lost and Damned has so much potential. While they stuck to the shooty-shooty bang-bang template here, Bully demonstrated that Rockstar can vary their gameplay while sticking to the open-world genre. Making a game where mayhem is not the core value proposition would actually be a better fit for the types of stories they've been trying to tell with Liberty City-- it would allow them to create a protagonist who is potentially not a sociopath.
Sam Houser, Rockstar's president, says that he likes the low cultural esteem of games because it gives developers license to do whatever they want. And since DLC have a higher profit margin and lower development cost than full retail games, it is a place where some experimentation might be financially feasible. If you keep the city and concentrate on putting more world into it, imaginativeness becomes the primary obstacle-- you can add things into this city without having to add much physical space and new assets. There's legions of empty storefronts and empty buildings, waiting to be filled. And media-- web sites, radio stations, tv shows-- don't take up space either. Think of this cheap empty space as a place to tell new stories, because as a developer, you are good at this.
Now that they've done so well with Lost and the Damned, why shouldn't Rockstar keep layering narratives into a consistent fiction? Tell a story in Liberty City from the perspective of a policeman, or a politician, or a dockworker, or a street kid. A city is a big place; there is no shortage of interesting people to simulate.
And you could switch up the gameplay: GTAIV already has a murder mystery in it, so why don't you try something on those lines? The short-form model would make it easier to accommodate the tentative experiments with player choice Rockstar tried in GTAIV proper. They could build on the player's familiarity with the world and its characters instead of making a headlong rush for the next graphical iteration.
I think GTAIV's graphics will look good enough for quite some time, and Rockstar has the clout to innovate in the console space. I hope I'm still driving around Liberty City for years to come. I don't know what Rockstar's long-term plans are for Liberty City, but I hope that they'll see it as a chance to establish a new genre of video game: the serialized post-human comedy.