@Jennkryst I don’t believe that’s accurate. The writers didn’t have a plan for Head Six. She was a Mystery Box because they thought it was cool. Even in a recent interview, RDM was still insisting that the final season writers’ room didn’t want to come out and call them “angels” because they didn’t want to put a name on it and kill the mystery.
There was a copy of the original BSG series bible floating around the internet years ago. Some relevant snippets:
Our show is built on the idea that a science fiction series can employ ground-breaking special effects, dynamic cinematography, realistic situations, believable characters and explore contemporary social and political issues without sacrificing dramatic tension or excitement.
(Our new) approach is to introduce realism into what has heretofore been an aggressively unrealistic genre.
We will eschew the usual stories about parallel universes, time-travel, mind-control, evil twins, God-like powers and all the other cliches of the genre.
My favorite aspects of the series were the things mentioned above. The fact that they extinguish the fire in the pod by venting it to space. The running count of people left alive in the fleet. The time they spend worrying about supplies. The commentary on social issues and moral dilemmas. Even most of Head Six’s original shenanigans could be attributed just to Baltar being insane (like when he points to the place they should strike on that one moon and then Six attributes it to “God guiding his hand”; they deliberately left it vague enough that maybe he just got lucky.)
So yes, quite clearly they ENDED UP where you describe, but I think there’s a ton of evidence that this was something they backed themselves into, and not a clear plan from the start.