Its an anthology show. This is not designed to go forever. This season is meant to be standalone
I mean not as anthological as True Detective. But not everybody will be continuing on this journey. The sort of central premise of time travel and Vandal Savage is totally up for grabs. This is meant to be a season that is tightly serialized that, when its over, you cant go home again. Its not going to begin Season 2 with us all hopping back on the same ship and like Lets get Vandal! Lets get him for real this time! This is not traditional episodic television.
Executive producer Marc Guggenheim chimed in to further explain the structure and compare it to FXs American Horror Story:
The way we think of it is each arc, each season is its own separate movie. What we want to do is have each separate movie have its own identity. So almost to the point where each season was telling one big story that you could sort of subtitle, like the way you do subtitle American Horror Story, if that makes sense