What If Nightwing lead the Arrowverse?

I've previously made a structuring of the way Arrow would've worked if the CW made a Batman TV show instead of a Green Arrow show due to the influence of Batman that was spread into the roots of the show. However, that doesn't extend to how the rest of the Arrowverse would work, so today I'm replacing Arrow with a Nightwing series that would create a television universe in the same way Arrow did (though at a smaller scale)

Nightwing
Airing: 2012-20

Seasons: 8

Plot: Fighting crime alongside the dark knight as Robin for ten years, Nick Grayson was growing tired of living in his adopted father's shadow and after a fight with Batman, Nick realizes he wants to be more than just Batman's sidekick. Nick and his girlfriend Barbara Gordon, under the new moniker of Batgirl move to Bludhaven to start fresh. Crimefighting isn't a walk in the park as Nick soon realizes and he is forced to question whether or not he is ready to fight on his own.

Protagonists:


 * Grant Gustin as Nick Grayson/Nightwing
 * Candice Patton as Barbara Gordon/Oracle
 * Willa Holland as Rose Wilson (S1)
 * David Ramsey as John Diggle/Spartan
 * Jesse L. Martin as Jim Gordon (S1-S7)
 * Katie Cassidy as Helena Bertinelli/Huntress (S1-S5)
 * Jordan Calloway as Michael Holt/Mr. Terrific (S1-S3)
 * Stephen Amell as Hank Hall/Hawk (S3-S6)
 * Minka Kelly as Dawn Granger/Dove (S3-S6)
 * Charles Melton as Garth/Aqualad (S6-)
 * Juliana Harkavy as Donna Troy (S6-)
 * Colton Haynes as Joe Wilson/Jericho (S7-)

Antagonists:


 * John Barrowman as Mark Desmond/Blockbuster (S1)
 * Manu Bennett as Slade Wilson/Deathstroke (S2)
 * The Court of Owls (S3)
 * Neal McDonogh as Damien Darhk (S4)
 * Josh Segarra as Heartless (S5)
 * Kirk Acevedo as Ricardo Diaz/The Dragon (S6)
 * Alexander Siddig as Ra's al Ghul & The League of Assassins (S7)
 * Willa Holland as Rose Wilson/Ravager (S8)

The Flash
Airing: 2014-23

Seasons: 9

Plot: Wally West aka Kid-Flash was the sidekick to his uncle Barry Allen aka the Flash for five years. However, after a fight with the Reverse-Flash, the Flash has vanished. In the six months since his demise, Wally has denied the mantle, stating that he doesn't want to tarnish the legacy of the Flash, even going as far as to quit being Kid-Flash to avoid questions of where the Flash is. However, due to the absence of a hero to instill hope into the hearts of Central CIty, crime has spiked higher than ever before, forcing Wally to act... fast.

Protagonists:


 * Jordan Fisher as Wally West/The Flash
 * Malese Jow as Linda Park (S1-S4)
 * Danielle Panabaker as Tina McGee
 * Carlos Valdes as Cisco Ramon
 * Danielle Nicolet as Iris West
 * Tom Cavanagh as Harrison Wells
 * Tyrel Jackson Williams as Danny West/Kid-Flash (S2-S4)
 * Violett Beane as Jesse Wells/The Flash (S2-S4)
 * Brandon McKnight as Ronnie Raymond/Firestorm (S5-)
 * Kayla Compton as Caitlin Snow/Killer Frost (S5-)
 * Andy Samberg as Ralph Dibny/Elongated Man (S5-)
 * Melissa Fumero as Sue Dearbon (S6-)

Antagonists:


 * Tom Cavanagh as Hunter Zolomon/Zoom (S1 & S8)
 * Teddy Sears as August Heart/Godspeed (S2)
 * Charles Michael Davis as Daniel West Sr./The Rival (S3)
 * Grant Gustin as Wally West/Savitar (S4)
 * Chris Klein as David Hersch/Cicada (S5)
 * Neil Sandlands as Clifford DeVoe/The Thinker (S5)
 * Sendhil Ramamurthy as Ramsey Rosso/Bloodwork (S6)
 * Efrat Dor as Eva McCulloch/Mirror Monarch (S6)
 * Rick Cosnett as Eddie Thawne/Cobalt Blue (S7)
 * Tony Curran as Despero (S8)

Supergirl
Airing: 2015-21

Seasons: 6

Plot: At 15 years old, Kara Zor-El escapes doom on planet Krypton to find protection on Earth. When Kara arrives, she discovers that 40 years have gone by. Having to now adjust to her new life, Kara must juggle her new responsibilities with her very human relationships.

Protagonists:


 * Lilli Reinhart as Kara Zor-El/Supergirl
 * Emma Corrin as Alex Danvers
 * Mehcad Brooks as Val-Zod
 * David Harewood as J'onn J'onzz/Martian Manhunter
 * Jeremy Jordan as Jimmy Olsen
 * Joshua Orpin as Conner Kent/Superboy
 * Tom Welling as Clark Kent/Superman

Antagonists:


 * Peter Fascinelli as Maxwell Lord (S1)
 * David Harewood as Hank Henshaw/Cyborg Superman (S2)
 * Odette Annable as Sam Arias/Reign (S3)
 * Lilli Reinhart as Linda Lee/Red Daughter (S4)
 * Jon Cryer as Lex Luthor (S5)
 * Peta Sergeant as Nyxlygsptlnz (S6)

The New Teen Titans
Airing: 2016-22

Seasons: 7

Plot: On a mission to investigate a child trafficking ring, Tim Drake finds Rachel Roth, a special girl possessed by a strange darkness, get involved in a conspiracy that could bring Hell on Earth. To combat this evil, Tim knows he won't be allowed to pursue this mission if an adult hero is accompanying him. As a result, Tim gathers fellow teen heroes and sidekicks across the country as together they become a surrogate family and team of heroes fighting evil.

Protagonists:


 * Leo Howard as Tim Drake/Robin
 * Cozi Zuehlsdorff as Rachel Roth/Raven
 * Curran Walters as Bart Allen/Impulse (S1-S6)
 * Nathan Anderson as Jackson Hyde/Aqualad (S1)
 * Iñigo Pascual as Jaime Reyes/Blue Beetle (S1-S4)
 * Karan Brar as Gar Logan/Beast Boy
 * Taylor Russell as Koriand'r/Starfire (S2-)
 * Brec Bassinger as Courtney Whitmore (S3)
 * Caleel Harris as Vic Stone/Cyborg (S3-S6)
 * Ashley Liao as Artemis Crock/Arrowette (S5-)

Antagonists:


 * Joseph Morgan as Sebastian Blood VIII/Brother Blood (S1)
 * Kiernan Shipka as Tara Markov/Terra (S2)
 * Manu Bennett as Slade Wilson/Deathstroke (S2)
 * Chandler Riggs as Jason Todd/Red Hood (S3)
 * Anna Diop as Komand'r/Blackfire (S4)
 * David Sobolov as Mongul (S4)
 * Doctor Arthur Light (S5)
 * The Enlightenment (S5)
 * Haley Tju as Jinx (S6)
 * The Hive Five (S6)
 * Josie Totah as Kitten (S7)
 * Esai Morales as Killer Moth (S7)