Star Trek: Picard answered many plotlines leftover from Star Trek: The Next Generation, but not about the fate of Sela
Although Star Trek: Picard gave fans closure over many plotlines from Star Trek: The Next Generation, giving Doctor Beverly Crusher a more active role, learning what happened to Ro Laren, finding out more about Guinan, and more, some plotlines were ignored or left hanging, including Sela, who literally ended her run as a character on TNG unconscious, never to be acknowledged or seen again on tv.
As PIC was much shorter than TNG it could not hope to cover every burning question fans had about what happened after many TNG episodes and some answers upset many fans such as the violent and unexpected death of Icheb (complete with Icheb being played by a different actor). Other characters or plotlines were referenced so that fans could fondly recall them but were not the focus of a plotline, such as a ship being named for Doctor Katherine Pulaski even if Diana Muldaur did not return to reprise the role.
One of the most glaring omissions is the lack of closure for a side character who was last seen being knocked unconscious, her potential was never realized when she could have been a true villain who changed canon forever. Sela, the daughter of a Romulan leader and an alternative timeline version of Tasha Yar, the security chief for part of the first season of TNG before she was killed on an away mission, was unceremoniously knocked out of TNG literally and figuratively. With all the time travel and follow-up to characters from TNG, Sela should have warranted at least a mention or brief scene to remind fans that she could have been a fully fleshed-out character, given proper plotlines if the writers had utilized her cunning and ruthlessness, instead of leaving her last scene being knocked unconscious by a Vulcan Nerve Pinch.
Star Trek: Picard should have given Sela the plotlines that Star Trek: The Next Generation did not
Many fans were excited about how PIC would continue TNG while making its own story. Fans got to see their beloved crew together again and revisit canon in new ways. Q and Picard became unexpected allies, aliens from other series were encountered by the crew, new species were created, and arcs were acknowledged or wrapped up. yet once again Sela was not given a proper send-off.
Sela did not receive some of the depth her mother’s fellow crew members did, but PIC was the perfect opportunity to do so. As the half-human, half-Romulan commander who attempted to over mine the Klingon-Federation alliance and then tried to halt Spock’s attempts to reunite Vulcans and Romulans, Sela could easily have become a political rival to Picard in much the same way Gul Dukat or Kai Win Adami became to Captain Benjamin Sisko on Star Trek: Deep Space Nine. Both of these DS9 antagonists tried to destabilize the Federation and Starfleet’s precarious presence on DS9, utilizing everything from political factions to religious unrest to force Sisko and his allies out.
There was even a tempting hint for a truly terrifying alliance as Sela supplied materials, including weapons, to the Klingon sisters B’Etor and Lursa, of the House of Duras. B’Etor and Lursa constantly worked against Picard in TNG, Sisko in DS9, the Federation itself, and to some extent the Klingon Empire to grab power for themselves, to the point that Gowron, the leader of the Klingon Empire, regarded them as ruthless and cunning. Their family, the House of Duras, had embedded themselves into the High Council so deeply that their own unscrupulous natures and lack of honor have given them far more power than other families. Sela herself was a brilliant strategist with a similar drive so had the three allied themselves to each other, they might even have created an alternate timeline where the Federation-Klingon alliance was replaced by Klingons overthrowing the Federation and the Romulans conquering the Vulcans. Would this alliance have created a new empire where the Klingons and Romulans worked together to oppress the Federation and Vulcans, turning the power structure of the Alpha Quadrant on its head?
Sela had the potential to be a true villain in the Star Trek franchise, ruthlessly overturning the power structure of the entire quadrant and had the alliance between her and the women who were really the power of the House of Gowron been built up, PIC may have been able to flesh out a very underutilized villain into the true threat to the Alpha Quadrant she could have been. As it stands now, Sela left the franchise in a very unfulfilling manner, leaving fans frustrated with how Sela followed in her mother’s footsteps.