Last thing I'll say about Future (and much of the later eps of the main show) is that it feels like it tries to be the Bojack Horseman of Cartoon Network, what with the protag having to deal with depression/mental illness, repressed feelings towards his family and everything he went through, unhealthy coping mechanisms, ect. All of that, but with magic/alien stuff. However, Bojack had the fortune of having semi-competent writers who could tackle the topics the show was trying to convey, such as the actual damage of being born to deeply broken people and handling said depression in extremely unhealthy ways (Bojacks copious drug and alcohol use), the lasting aftermath of lashing out, and what it's like carrying so many toxic, intrusive thoughts. That, and Future only had a handful of eps to wrap everything up. Oh, and the dead people stayed fucking dead, much like real life.
Steven had Greg, Connie, the Gems, most of the townies, fucking everyone adoring him and actually liking him enough to give him that stupid ALL-HEALING hug at the end. I don't care if they showed him going to therapy, the whole ending was rushed and stupid.
Bojack had no family actually liking him, most of his friends either alienating/distancing themselves from him (Todd, Princess Caroline), or dying (Directly: Sarah Lynn, Indirectly: Herb) or leave his life (Hollyhock) BECAUSE of him.
TL;DR: The washed-up, drunk horse man is more accurate to depicting a damaged person than the space rock Messiah.