So the second season of this dropped recently. It seems to wrap everything up, I'm not sure if it was planned to only be two seasons or if they were given the notice mid-production and said 'eff it if we're only going to have two seasons then the last episode will be a movie!' because, uh, the last episode clocks in at well over an hour.
Probably the most surprising twist is that the seemingly obvious parallels between Horse and the Nowhere King were a bit misleading. The Nowhere King did have a relationship with the other human woman in Centaurworld, but not as rider and steed. Turns out the Nowhere King used to be a Centaur (well, Elktaur) and became infatuated with a human princess and after convincing himself that she would never love him as he was he devised a way to split himself into two beings, human and elk. Unfortunately both parts had all the same memories and feelings, so while the human went on to marry the princess, the elk could only watch from afar, and one thing led to another, something something horrifying monster war.
But all of that is revealed in just the last episode. The other seven leading up to it are more or less more of the same from season 1. We do get some more backstory on the herd, and an uncomfortable amount of Comfortable Doug, and plenty of songs. So you probably already know if you want to see more of this on what you thought of season 1, just have time set aside for that last episode and don't start it up expecting the usual 20-30 minute affair. Not that I did that or anything.