With the show having so many characters it's only inevitable that a few would end up underutilized.
- In the earliest episodes of the show, the AV Club noted that the writers didn't seem to know what to do with Selina Kyle, as she was commonly reduced to a few token scenes stalking around silently in each episode. She managed to grow out of this later on.
- Harvey Bullock began as the corrupt cop who made sure other cops "toed the (mob's) line" before he went through a Heel–Face Turn in "Penguin's Umbrella". Afterward, he became the cop who was so jaded from fighting corruption that he simply "gave up" and went along with it. This later S1 characterization came with Bullock frequently giving advice to Gordon to be more pragmatic, which provided an interesting dynamic in his relationship with the more idealistic Gordon. However, after S1, Bullock was relegated to the sidelines, being used for comic relief or do actions that would move along Gordon's story, with his previous characterization essentially forgotten. Until S4, that is, where this characterzation and the conflict it causes with Gordon resurfaces with a vengeance.
- Kristen Kringle was nothing more than a device to start Ed towards his descent into villainy, when she and Ed had great chemistry on-screen that could have been explored.
- The Dollmaker seemed to be set up as a Greater-Scope Villain that would dwarf the mob bosses. Turns out he's just some crazy doctor who does illegal surgeries. And he was nothing more than an obstacle to keep Fish out of Gotham for a few months.
- Dick Lovecraft. He was nothing more than an obvious Red Herring, instead of a viable suspect in the Wayne case.
- The Electrocutioner also gets this. The show managed to make him into a very impressive and imposing sort of electricity-based philosophical madman (no doubt aided by the portrayal of Christopher Heyerdahl), but he's dispatched very quickly and anti-climatically shipped back to Arkham.
- Remember Montoya and Allen? How they were becoming allies of Gordon and were going to investigate the Wayne murders in his place? Yeah, they were written out of the show midway through Season One without mention.
- Richard Sionis could have been a major player in the Gotham underworld, acting as the precursor to Black Mask. And just as the show brings him back, he gets stabbed to death.
- Anyone else disappointed with the death of Jerome so early in Season Two? He made for a great candidate for The Joker, but with his death, any development of that idea is lost. Until Season 3. He's Back!.
- At the end of the first half of Season 2, Silver St. Cloud pulls a Heel–Face Turn and reveals she's developed real feelings for Bruce. So, what does the show do with her next? Absolutely nothing, as that is her final appearance and we never see her again.
- Puck, Gordon's heroic Nice Guy sidekick who stands up for him in prison despite knowing full well the danger of getting his ass kicked, and then dying from those injuries, off-screen, while the other characters are talking. Had he survived, he could have been a criminal informant for Gordon in place of Penguin or even a minor villain.
- The Penguin's father. Hyped up as being played by Paul Reubens once again, being a complete and sympathetic 180 from that incarnation, and still loving his long-lost son despite knowing full well about his crimes, Mr. Cobblepot had the makings of being another Morality Pet for Oswald after the death of his mother. Instead, after just a couple of episodes, the father was accidentally poisoned to death due to inadvertently drinking some poison meant for Oswald — and all in a textbook Ironic Echo of his mother's death, too. And just to add insult to injury, this happened in the same episode as Puck.
- Karen Jennings is a Creepy Awesome, not to mention badass, Woobie who knew Bruce's father, would have made a great Creepy Good ally foreshadowing Bruce's own dark future form and gives herself up before the end of her introductory episode right after Gordon, Alfred, and Bruce broke her out of jail in almost exactly the same way as Puck.
- Azrael gets unceremoniously blown to smithereens by an RPG before establishing the sinister presence he has in the comics.
- The nightclub owner, Jeri (Lori Petty) from "Wrath of the Villains: This Ball of Mud and Madness". She had her face painted just like The Joker's was and was as charismatic and snarky as The Joker, making some fans believe she could have turned into the eventual Joker. Alas, all she was used for was to move along the plot of Bruce investigating his parents' murder.
- Valerie Vale, due to being a disposable love interest for Gordon.
- Alice Tetch; a young woman who's been through a hell of a lot, an object of obsession for her brother Jervis, with a horrifying and compelling backstory. Dead after just two episodes, with her freaking blood having a bigger role to play in the story than her.
- Sal Martinez, a member of the GCPD's Strike Force and an expert sniper; despite having been written up with a good backstory and known for successfully managing to hit Zsasz, he was disgracefully murdered by Tabitha Galavan in his fourth appearance (in a close quarters fight, no less).
- Josie Mac, the token woman and sole surviving member of the Strike Force, abruptly stops appearing after "By Fire". It's possible that Officer Parks in "A Bitter Pill to Swallow" was meant to be her.
- Harvey Dent, who is destined to become Two-Face. He appeared to be set up as a great ally to Jim Gordon and his quest to taking down the mob, whilst at the same time perhaps having his own personal issues, due to losing his temper with Dick Lovecraft (a clear foreshadowing to him becoming Two-Face). Despite the actor being promoted to regular status for season two, he only appears in three mere episodes and after the season is never mentioned again, with the potentiality of exploring the Dent character being thrown out the window. And bizarrely enough, the potential plot of him dealing with his darker personality is given to Edward Nygma/Riddler, which becomes a long running arc for him throughout the next few seasons of the show.
- Speaking of Nygma/Riddler, starting with season 4 his role has been reduced to a Satellite Character, either as Lee's Romantic False Lead or Penguin's Heterosexual Life Partner.
- Sofia Falcone. She entered S4 playing everyone she met- Gordon, Oswald, her father- like a fiddle, portraying the kind of Magnificent Bastard that you'd expect a top mob boss to be. She could have been a formidable villain for several seasons, but she only lasted half a season just to give Gordon (an admittedly deserved) "Reason You Suck" Speech before being unceremoniously dumped after getting shot in the head and put in a coma.
- 514A, the Indian Hill clone of Bruce, offered the intriguing prospect of removing Bruce's Plot Armor. However, rather than get a long-term storyline to provide tension, the clone disappears after being recruited by the Court of Owls.
