It confirms that this Gordon is a Gotham native, not from Chicago, and an optimist about his job from the get-go. Also him and Bullock are the first responders to the Wayne murders.
I think this includes the first offical mention of a 'young Joker' as well.
The rest of the details are things we've already heard or guessed before.
Everyone knows the name Commissioner Gordon. He is one of the crime world's greatest foes, a man whose reputation is synonymous with law and order. But what is known of Gordon's story and his rise from rookie detective to Police Commissioner? What did it take to navigate the multiple layers of corruption that secretly ruled Gotham City, the spawning ground of the world's most iconic villains? And what circumstances created them – the larger-than-life personas who would become Catwoman, The Penguin, The Riddler, Two-Face and The Joker?
"Gotham" is an origin story of the great DC Comics super villains and vigilantes, revealing an entirely new chapter that has never been told. From executive producer/writer Bruno Heller ("The Mentalist," "Rome"), "Gotham" follows one cop's rise through a dangerously corrupt city teetering on the edge of evil and chronicles the birth of one of the most popular super heroes of our time.
Growing up in Gotham City's surrounding suburbs, James Gordon (Ben McKenzie, "Southland," "The O.C.") romanticized the city as a glamorous and exciting metropolis where his late father once served as a successful district attorney. Now, two weeks into his new job as a Gotham City detective and engaged to his beloved fiancée, Barbara Kean (Erin Richards, Open Grave, "Breaking In"), Gordon is living his dream – even as he hopes to restore the city back to the pure version he remembers it was as a kid.
Brave, honest and ready to prove himself, the newly-minted detective is partnered with the brash, but shrewd police legend Harvey Bullock (Donal Logue, "Sons of Anarchy," "Terriers," "Vikings," "Copper"), as the two stumble upon the city's highest-profile case ever: the murder of local billionaires Thomas and Martha Wayne. At the scene of the crime, Gordon meets the sole survivor: the Waynes' hauntingly intense 12-year-old son, Bruce (David Mazouz, "Touch"), toward whom the young detective feels an inexplicable kinship. Moved by the boy's profound loss, Gordon vows to catch the killer.
As he navigates the often-underhanded politics of Gotham's criminal justice system, Gordon will confront imposing gang boss Fish Mooney (Jada Pinkett Smith, The Matrix films, "HawthoRNe," Collateral), and many of the characters who will become some of fiction's most renowned, enduring villains, including a teenaged Selina Kyle/the future Catwoman (acting newcomer Camren Bicondova) and Oswald Cobblepot/The Penguin (Robin Lord Taylor, "The Walking Dead," Another Earth).
Although the crime drama will follow Gordon's turbulent and singular rise through the Gotham City police department, led by Police Captain Sarah Essen (Zabryna Guevara, "Burn Notice"), it also will focus on the unlikely friendship Gordon forms with the young heir to the Wayne fortune, who is being raised by his unflappable butler, Alfred (Sean Pertwee, "Camelot," "Elementary"). It is a friendship that will last them all of their lives, playing a crucial role in helping the young boy eventually become the crusader he's destined to be.