From codependency to freedom: Sophie's journey with love
I think about that shot of the original crew in front of the black book in the finale: Sophie between Parker and Eliot; Nate between Parker and Hardison. Between each pair, they will compensate for Nate and Sophie's departure respectively. A rewatch of seasons 4 and 5 shows how they slowly were increasing the ot3's roles in the cons and decreasing Nate and Sophie's.
It's a necessary and bittersweet moment.
Leverage bookends seasons but always leaves the door open. There was always more story to tell about their development as a family. There was a season 6 bouncing around the writers' minds, and that's not what we get in Leverage: Redemption, but the story picks up organically. Because Sophie's at this impasse. She's lost her life partner, and Eliot, Parker, and Hardison have been enough for each other for nearly a decade. Longer than they ever worked together with Sophie.
They do not need her.
I argue that the ot3 doesn't need each other either, not if you compare it to the beginning of s2 where the reunion was very cute but also codependent and unsustainable. But while they consider Sophie to be family, she is not in their ot3 family unit. They helped each other get over their grief. Sophie stood alone (more on that later).
They do not need Sophie anymore and haven't in a while, but they want her badly.
And that's it. That's the point. "I didn't choose the others. I picked you," Nate tells Sophie in The Lonely Hearts Job, about the way the crew began. In season 5, he chooses her again, over his self-violence. He comes to call the crew family, but he commits further to Sophie like the ot3 does.
Leverage: Redemption begins with the ot3 choosing Sophie, for the first time since they met, out of want and not need. It ends with her choosing them under the same circumstances.