Warning! Spoilers ahead for The Batman
Following the Penguin spin-off series can provide new insights into the city's transformation into the modern-day Gotham.
Following the death of crime boss Carmine Falcone in The Long Halloween storyline from Jeph Loeb and Tim Sale, Gotham underwent a massive paradigm shift where the rules changed. Organized crime was no longer the dominant power in Gotham, seeing as how it had begun to give way to the dawn of the supercriminal (Batman's rogues' gallery). As such, the death of Carmine Falcone's "The Roman" was the final nail in the coffin and his expansive criminal empire quickly dissolved. However, Penguin is one of the few Batman villains who isn't crazy, serving as one of the last holdouts of organized crime in Gotham which he runs from the Iceberg Lounge.
The same largely holds true for Matt Reeves' vision for Gotham in The Batman. In the film, Oz is a lieutenant to Carmine Falcone (played by John Turturro), running the Iceberg Lounge (and the secret mob club within known as 44 Below). Following Riddler's plan to flood the city and his murder of Falcone, Gotham is poised for a similar transformation as the city begins to rebuild, including what will no doubt be a reformation of its criminal elements. As such, it's heavily teased that Penguin will be stepping up to claim the same levels of authority he has in the comics. Likewise, his confirmed spin-off series coming to HBO Max can show Gotham's transformation through the eyes of Penguin as he seeks to consolidate power for himself.
While Falcone was largely positioned against the supercriminals in The Long Halloween and was barely able to tolerate them, Penguin is more flexible. Historically, he has embraced the chaos Batman's villains present and taken advantage of the opportunities that present themselves. While it's easy for Penguin to be depicted as a joke and underestimated, it certainly seems as though Matt Reeves and Colin Farrell's version of "Oz" will be quite the force to be reckoned with as he works to create his own empire in the wake of Falcone's death.
As Gotham enters this time of reformation following The Batman, there will no doubt be plenty of obstacles and challenges for "Oz" to face in his spin-off series. It's also going to be interesting to witness his unique perspective on the changes happening to the city. While Farrell's performance certainly helped earn his own series, there's truly no better character to be featured during this transitional period, seeing as how Penguin is a product of the old Gotham who's cunning enough to embrace what's to come in the aftermath of The Batman.