Room For More
It’s Diana’s line that follows Bruce’s speech that really sows the seeds for the future, though. In response to his “six chairs” comment, Diana adds: “But room for more.” Bruce concurs and repeats: “But room for more.” Basically: the Justice League is open to new recruits.
With a slew of other DC movies currently in the works at some stage of development, there are a wide range of characters who could join the League in future outings. Green Lanterns Hal Jordan or John Stewart are obvious candidates, but you can also bet that Zachary Levi’s Shazam will rub shoulders with the other heroes once his own film arrives, likely in 2019. Batman’s sideckicks Nightwing and Batgirl could also potentially join the League.
If Justice League 2 wants to introduce characters from scratch, though, that opens the net even further. DC producer Charles Roven has spoken about his interest in seeing Martian Manhunter in the DCEU, for example. And the JL cast recently suggested they would like to see more female members such as Black Canary, Supergirl and Zatanna. Plus, fans are repeatedly calling for Charlie Hunnam to don Green Arrow’s hood at some point.