They already answered who the gate builders are. Vogans.
How did a declared strident conservative such as yourself, find that story satisfying? The most vain, egocentric, liberal all talk, do nothing character was given the save the day. Half the final was listening to that moron saying "I understand," "I've fought," blah, blah, blah. She wrote speeches, for self-serving purposes, to make it seem as if SHE was making the difference. Two million people died for her arrogance. She left her family so she could see something unique, be a part of history. SHE didn't expose Errinwrite, as she's given credit. That credit goes to the character left out of the story. And let's not gloss over that the other "hero" was another self-serving killer, Mao.
The person who should have been on that ship, with the character built cache to actually pull off the final plea was left out of the script, as opposed to someone that no one knew. Chrisjen should have been on the ship and the alterior story motive, should never have existed. The "reverend" never had a point to the story that wasn't forced and about the only way that can be redeemed is if she gets recognized for what she is and gets her comeuppance
They were warriers, all three sides. The story did a bad belly-flop in how it got everyone to trust and turn off the reactors. They trusted the all-talk, no responsibility liberal and the media. lol.
I agree there is a lot of promise in the story for next season. I like how they keep reinventing instead of beating the same horse that's the doom of so many great shows. I noted that in Holden's (snore, can the ring create a new actor) final monologue he picked up on Ashford's reasoning for trying to destoy the ring, the human's by their nature will make it worse if they can get past the ring.
Straithairn's acting is superb. Unrecognizable to any other character I've seen him do, an almost impossible task for a recognizable actor. Cara Gee is another who makes her screen time a pleasure.