This is what annoys me about S2 so far (I am sure it will get better), but this is pretty much what I thought was going on. They used the first half of the season to get Legends of Tomorrow out there and ignored most of main stories. I really did feel like the first half was just a bunch of fillers for Legends and very small portions that focus on the Flash story.
After Arrow and The Flash helped launch the new CW series DC's Legends of Tomorrow during the first half of each show's seasons, both series will refocus their storylines on their respective central villains once Legends premieres on January 21st.
On The Flash side, showrunner Andrew Kreisberg promised a similar focus on Season 2's Big Bad, Zoom.
"The rest of the season is really focusing on Zoom and the Multiverse," he told reporters at TCA. "The early parts of seasons are really hard because you're setting things up. For us, that was sort of what the fun of Legends was was getting to bring all these characters on and having them fill out these early episodes while still being tied into the main narrative. But now for Arrow and for Flash, on Arrow it's Oliver versus Darhk and on Flash it's Barry versus Zoom, and that's really where the focus for both of those shows lie."
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