Bungie’s community manager Cozmo confirmed on the Destiny subreddit that the two modes would not be returning in Destiny 2’s Season 5: Season of the Forge. While he did not give any further explanation as to why Faction Rally would not return this new season, Cozmo did specifically say the developer is still working on Trials to meet player expecations:

Both Trials of the Nine and Faction Rally were a point of contention among players, with a generally negative feeling towards both activities. For the most part, longtime fans who played Destiny 1 were never really happy with Trials of the Nine’s departure from the original game’s Trials of Osiris 3v3 Elimination mode. Even though Destiny 2 took a chance on changing the PvP endgame mode, it never really landed for players in the same way Trials of Osiris did. And so Bungie put Trials on hiatus.

Similarly, Faction Rally was a departure from Destiny 1’s factions system. Bungie did switch up Faction Rally in Season 3 to make player choice matter more and have the event require some more dedication to earn its greatest rewards, but the monthly event had a hard time finding the right balance. Players either complained that it was too easy and didn’t have much of an impact or that it was too hard and required too much dedication for a single week.

While some players may have been hoping that Trials and Faction Rally would finally make their triumphant returns in Season 5, it looks like they’ll have a longer wait while Bungie is taking longer to redesign these activities for players. Season 5 runs for three months from December to February.

Destiny 2: Black Armory releases December 4, 2018 for PC, PS4, and Xbox One.

Source: Destiny The Game Reddit