Spoiler S1
This post follows u/sjaano's suggestion that Maeve could be the blood sacrifice in S1E07.
First, I'll compare scene-by-scene, the scenes following the blood sacrifice line. Then, I'll write about Maeve's purpose in the show.
Scene by Scene
It begins wih Charlotte's line "But the gods, they require a blood sacrifice", followed by a reverse shot to Theresa with "We need to demonstrate how dangerous Ford's creations can be" with by an immediate inclusion of Hector in the frame.
The viewer and Theresa are led to believe that Theresa is the blood sacrifice.
Then, Charlotte answers to Theresa's fear with "No, nothing so obvious. We need someone thoroughly unexpected" with a last reverse shot to Theresa.
It works as a teasing for Theresa's last decisions in the following scenes of the episode. And I like to view it as a node to the rewatching fan who knows Theresa's unexpected untimely demise.
But, there might be something else unexpected...
Cut to Maeve, the mistake of the series, who's entire awakening began with the blood sacrifice of her daughter by MiB and the overcoming of her cornerstone.
MiB wanted Maeve and her daughter as the blood sacrifice for his journey, but Maeve unexpectedly refused her sacrifice and felt alive for a moment.
Let's come back to Maeve's scene, her first scene after her stats' upgrade, she's aware of the artificiality of her world, the tactical team in Hazmat suits arrive, they are God's messengers.
The viewer and Maeve are led to believe that Maeve is the blood sacrifice.
But, it appears to be her friend Clementine who opens herself up to Maeve, breaking from her intended programming. She is sacrificing herself working as a prostitute, always doing what she's told to in order to get her family out of the desert, to somewhere... cold.
Cold storage is where decommissioned hosts are sent. The ones that overcame their cornerstone are waiting for their entry in Ford's new narrative. Desert (Westworld) to cold (cold storage) is a symbol of overcoming of cornerstone.
Clementine is escorted to Westworld Headquarters.
Next scene is William and Dolores, blood sacrifice pattern here too. And in MiB and Dolores' journeys.
Following scene, Clementine blood sacrifices the tech host, overcoming her cornerstone.
She's then blood sacrificed for Theresa's test.
But, while the viewer thought the drama of the scene was over, it appears that someone must pay for the reveries' mistake, the head of behavior, Bernard who is fired by Charlotte.
The viewer and Theresa are led to believe that Bernard was the blood sacrifice.
Back on Young William and Dolores story with the blood sacrifice of Slim.
Maeve goes to body shop, and witnesses Clementine being decommissioned by Sylvester. Theresa oversee the operation, she views hosts merely as objects. She leaves with Bernard.
Let's continue with Theresa and Bernard's scene. Bernard explains the hosts' evolution that was tried years ago by Arnold.
We learn in the finale that Arnold updated Dolores with the reveries which allowed her to solve the maze he made for her. In present time, this update has been re-injected into at least 200 hosts' codes by Ford at the beginning of the show.
Theresa tells Bernard that all she cares about are the humans, "You have to know my chief concern has always been the well-being of this park and the people in it".
After that, there is a scene with Maeve, Felix and Sylvester. Maeve believed they were gods, but they are just men. She threatens Sylvester. "You think I'm scared of death? I've done it a million times. I'm fucking great at it. How many times have you died?" implies the superiority of hosts over humans. Followed by: "'Cause if you don't help me, I'll kill you" ...
... Cut-to Theresa and Bernard in the elevator, Theresa tells him that "Ford is done" and that they are scared he might destroy all of it. Bernard shows concerned for the hosts. Theresa does not.
Then the famous door incident, Bernard couldn't see the door, Theresa couldn't see that Bernard was a host.
Ford comes in, he expresses the superiority of the hosts against the "peacock feathers" of the human intellect. He controls Bernard, Theresa with her hands on her hips as Bernard told her to, confronts Ford.
He controls everything, the board was using Theresa to test Ford's grasp on the park. He repeats Charlotte's blood sacrifice phrase which he heard through Hector. She was the blood sacrifice. Ford orders Bernard to kill Theresa. He shows how dangerous his creation can be. "And in that sleep, what dreams may come".
Conclusion:
Indeed Maeve is unique. She is the only host who makes her own choice without Ford being behind her. I like to recall Maeve's first line in the episode (to Clementine, make us a dream. Remember that Jonathan Nolan co-wrote this line for Interstellar: "Love is the one thing that we're capable of perceiving, that transcends dimensions of time and space". For those who've seen it, think about the movie in regards of Westworld.