Forsaken in terms of storywise was probably Destiny's best expansion ever. You go in to avenge Cadye by shooting Uldren, and along the way you slowly uncover this whole fucking mess involving The Last Ahamkara, the Cunning Witch Queen, and their plan to fuck over the last of the Awoken and their City. And then actualy entering said city and meeting the Techions who got took... all of it awesome.
The one thing I will give Shadowkeep over any other expansions was the feeling of turning that corner and seeing the pyramid ship.
I had the privilege of standing behind Byf when he turned that corner. :)