AN is working on new ways to experience past Living Story events in the game. But that will take time, and will most likely not involve simply “replaying prior content” but rather other ways to experience the story aspects.
While AN keeps reminding us that the Living Story can and will bring features normally only seen with the release of expansions (major skill/trait/gameplay updates, new zones, etc.), they also keep saying that the idea of expansions is still very much on the table.
It is only the stand-alone campaign model they have abolished, since it won’t work with the Living Story.