Star Wars: Ahsoka Explores New Galaxy, Paving Way for Future Stories

Series creator Dave Filoni, now Chief Creative Officer at Lucasfilm, credits George Lucas and the Prequel Trilogy for the idea of exploring other galaxies.

Star Wars: Ahsoka takes the franchise to an entirely new galaxy, Peridia, for the first time, continuing the story of former Jedi Ahsoka Tano and Sabine Wren as they search for Ezra Bridger.
Series creator Dave Filoni explains that the decision to move the story to a new galaxy was necessary to explain the long absence of Thrawn and Ezra, arguing that they would have been found if they were still in the primary Star Wars galaxy.
Filoni credits George Lucas and the Prequel Trilogy for the idea of exploring other galaxies, referencing a scene in Attack of the Clones that shows the main galaxy and several smaller ones nearby.
As the newly appointed Chief Creative Officer at Lucasfilm, Filoni is planning for a 'long game' with his projects, setting up a larger conflict with the Imperial remnant that will be visually different from previous conflicts in the Star Wars universe.
The season one finale of Ahsoka suggests that we will see more of Peridia and its galaxy in future Star Wars stories.