One of the points of contention following the well-received "Crisis on Infinite Earths" crossover was how John Diggle wasn't done justice at all. Oliver Queen died twice and both times he wasn't there holding his friend's hand -- which is understandable as there were a lot of moving parts narrative-wise.
Still, you can't help but feel Diggle deserved better than being a throwaway face, and seeing as the Arrow series is now spinning off into Green Arrow and the Canaries and he's just gotten his Green Lantern ring, it'd be a great move for all to let him head over to Black Lightning to remain a prominent figure in the Arrowverse.
Now, Diggle's moving his family to Metropolis so we can expect more of him and his cosmic adventures in Supergirl or the upcoming Superman & Lois series. However, we don't know if he's also being eyed for the HBO Max Green Lantern series, so as it stands, Diggle's going to be learning about his ring with the Martian Manhunter and Co. But there's no reason he can't start his initial investigations over in Freeland. Going over to Black Lightning allows him to own more of his character as a black man and teacher, and someone who can really finesse Jefferson Pierce into a soldier for the Justice League as well.
It'd also be great to have Diggle learning from Jeff, too, as the latter's an educator and very experienced in combat. Diggle and Gambi could also form a great partnership -- talking shop with tech and weapons in a way similar to his tenure on Team Arrow. Jeff's squad has a bit more of a militant edge to it under Gambi, so Diggle fits in perfectly as his stepfather was a military man as well, plus with his daughter back in the land of the living, dads taking care of girls is a theme that writes itself in this series.
With Jefferson's daughters, Anissa and Jennifer, also going through the burgeoning superhero motions, Diggle can help train them like he did heroes on Team Arrow. Both sides of the coin fit each other so well, and while this seems like a radical change, having Diggle in a world with heroes who control electricity, heat, thunder and lightning places him front and center in the non-grounded area "Crisis" created for the entire Arrowverse.
There are just so many things in Freeland that would allow Diggle to shine; things like black youth being at-risk, his mixed-race kid, young metahumans on the lam, the ASA basically being an evil agency ready to throw humanity under the rug, and also, the war Markovia is bringing to America. He needs to be a big dog in the fight, not a peripheral character again, and Black Lightning offers him that spotlight because Jeff needs a brother-in-arms. Diggle could be the solution to this with Jeff also helping him prepare for his galactic responsibilities ahead.
Even if it's an extended stay or constant visits from Metropolis, Diggle could investigate Freeland's incorporation into Earth-Prime after Ollie rebuilt the Multiverse, so the project doubles as a mission for him. After all, there are a lot of metas they should be taking note of for the next Crisis in case they're in need of more allies and potential members for the League.
Diggle could also help ease the bridging between the multiple shows by being the everyman, a la the MCU's Nick Fury. More so, this gives closure to him as someone raising a family in a very family-centric series and adds to his journey as a former ARGUS operative who knows that reality is officially much bigger than they thought initially.
The vibe he has, his swag and the way he moves smoothly fits everything Jeff's about, as well as Freeland, so it's a win-win for everyone. You'd also get Arrow fans coming over to Black Lightning and an organic connection to everything in the greater TV-verse. In other words, it's not that shocking a concept because it feels natural to have someone like Diggle in an area like Freeland that needs all heroes on deck to help establish order. This is even more necessary with Jeff's biggest ally, Chief Henderson, being written out for next season. Plus, when it comes to saving cities, Diggle rarely fails. We can picture him and Jeff being an epic one-two combo no one would ever see coming.
We don't know when Diggle will make the trip to Oa but just because he's a Green Lantern in-the-making, that doesn't mean he can't help Jeff spread some light in Freeland -- other than the electricity Black Lightning shoots.
Airing Mondays at 9 p.m. ET on The CW, Black Lightning stars Cress Williams as Jefferson Pierce/Black Lightning, China Anne McClain as Jennifer Pierce, Nafessa Williams as Anissa Pierce/Thunder, Christine Adams as Lynn Stewart, Marvin "Krondon" Jones III as Tobias Whale, Damon Gupton as Billy Henderson and James Remar as Peter Gambi.