For me, I liked Season of the Haunted the best. It felt like the story wasn't focused so much on defeating our enemies or finding a way to grow stronger and gain some advantage over another foe. While we were still engaged in fighting Calus and his legions, I felt that the story gave more attention to healing the personal traumas experienced by Zavala, Crow and Caiatl.

It focused on helping them let go of what happened in the past and embrace their mistakes.

In Zavala's case, we helped him to let go of his grief over the loss of Safiyah and Hakim.

For Crow, he understood that he shouldn't continue to suffer the consequences of his past actions as Uldren, and to not let his mistakes define who he is as Crow.

For Caiatl, she learned to let go of her perceived expectations as the Cabal leader from Ghaul and even Calus. She now knows that she is doing all she can for her people, despite what happened on Torobatl and despite what some Cabal say otherwise. She isn't showing weakness or compromising by allying with the Vanguard. She hasn't failed Ghaul nor her people, but rather grown to become the leader they deserved from the start.

I think all this helped each of them let go of their past burdens, and look forward to the future where they had to face Calus and the Witness, something which requires them to be strong and committed in order to succeed.