Sharon Carter is a character that has always struggled to find her place in the Marvel Cinematic Universe. She was rejected by fans as Steve Rogers' love interest, in large part because she was replacing her great aunt, the beloved Peggy Carter. After becoming a fugitive in Captain America: Civil War, Carter became such an afterthought that she was cut from Avengers: Infinity War and her being a victim of the Snap was barely noted in Avengers: Endgame.
Her heel turn as the Power Broker in The Falcon and the Winter Soldier has given her a niche that doesn't tie her to Rogers or S.H.I.E.L.D. While it can be argued that this move finally gives Carter her due, rumor has it that it won't lead to a bigger role in the next Captain America movie. That might be for the best, as her story is better suited to another medium: television.
A Power Broker series' most obvious benefit for Carter's character development is that it allows (and forces) Marvel Studios to show its work with her evolution. While it gave her a more interesting role than love interest, Carter simply hasn't had enough screen time for her new role to feel earned. It's just something that happened off-screen to maneuver her into a new role, without really enriching her in-universe.
Making her Power Broker origin story the focus of a Disney+ show could make her journey real to MCU viewers, who haven't had much to latch on to with her character that they didn't bring from the comics. It could also provide a compelling story regardless of fans' feelings about the character. Carter went from a woman without a country to a powerful figure in Madripoor's cutthroat underworld. That's a journey worthy of a television series.
Carter's descent into supervillainy, or at least anti-heroism, could also bring something new to the MCU's slate of spin-off shows. While the anti-hero's journey is well-trod territory in prestige television, from Breaking Bad to The Sopranos, it's new territory for the MCU. That's especially true for a character going from a trusted ally of the Avengers to a shadowy crime boss. Carter's arc could also be a good contrast to Loki's, given how he's grown into a more sympathetic figure over the years. It could also give fans a new appreciation of Carter, as people love a good anti-hero more than a heroic second banana.
The series could also take place in a time audiences have seen little of in the MCU. Carter used the Snap to fake her own death and establish her empire. The MCU has barely scratched the surface of what it was like in the time between Thanos eliminating half of the universe and the events of Endgame. A Power Broker series could explore that through a unique setting in Madripoor, which could provide perspectives outside of the norm for the franchise.
Additionally, Carter's status on the criminal fringes of the MCU could introduce some characters that would thrive in that space. Beyond more appearances from the late, lamented Batroc the Leaper before his untimely death, it could introduce other unsung Captain America villains, like Zaran/The Weapons Master and Machete. It could also introduce some of Madripoor's resident heavies, like General Coy, Roughouse and Bloodscream. More sympathetic characters like crime-boss and Wolverine ally Tyger Tiger could also be in the mix, assuming Marvel doesn't want to save those characters for Wolverine's MCU introduction.
A Power Broker series could add depth to Sharon Carter's character and the MCU as a whole. Making her evolution from S.H.I.E.L.D. agent to powerful crime boss actual "text" in the MCU could do more than flesh out the complexity of Carter's character: it could give her future MCU appearances more gravity. If executed to its full potential, it could even make a compelling argument for her earning the antagonist role opposite Sam Wilson in a future Captain America movie.