These past few years DC became such a prominent player on TV with its CW's shows, Arrow, The Flash and Legends Of Tomorrow. When we thought that it was all, we got Constantine, Vixen and now Supergirl on CBS.
The Supergirl/The Flash crossover is eagerly awaited by fans, as until a few months ago, it wasn't sure whether or not the Girl Of Steel could eventually meet other DC heroes on TV. Now we can start to think about much bigger things in a near future, as hinted Grant Gustin when talking about Barry's upcoming comic-booky scene with Kara:
“It’s close.” Hopefully close enough that they’ll need a rematch next season, maybe with Green Arrow and the Legends as an audience. “That’s in the cards at this point,” says Gustin. “The whole point of us doing this crossover is setting up the fact that maybe next year we can cross over all of them.”
Gustin's statement makes sense if you think about it. His appearance on Supergirl could lay the groundwork for a much more ambitious story. Could you imagine a 4-hour crossover event between Supergirl, The Flash, Arrow and the Legends Of Tomorrow? It's possible that it is actually what WB is planning for the next year.
It's surely what comic-book fans are dying to see at this point, and Barry's power combined with Rip Hunter's time-ship could probably allow that. It would certainly be the closest thing we'd got to a Crisis On Infinite Earths storyline and it could attract more people to watch all shows. For my part, I'm totally on board!