The Extremes require comparatively less coordination/teamwork/DPS/mechanics compared to Savage. That's why they're at a lower tier to Savage in difficulty, not because they don't require anything at all. If you think mechanics like Final Liberation don't require coordination for groups to navigate through then you're either completely naive or ignorant.

You know an example of a Trial that required little of the above? Steps of Faith, and look how that turned out. Reality is, the only reason DF stuff works out in this game is due to the content being set up to be clearable with minimum effort (whether on launch or through nerfs/echo/gear). On top of all that, you get video/written guides available telling you what to do and when.