Well, this is what I found so far after playing the Alpha regarding this new game mode. "Galactic Assault is a forty player game mode in Star Wars Battlefront II that spans all three trilogies and has objectives that are unique to each planet. At EA Play 2017, Galactic Assault on Naboo: Theed featured Separatist forces trying to storm the royal palace, protected by Galactic Republic clone soldiers. Dennis Brännvall, Associate Design Director of Battlefront II, stated that Walker Assault, a game mode from the first game, would make its return as Galactic Assault on Hoth."