Very interesting, Alex. I had only come across Steven Universe on occasion when the kids happened to be wtahcing, and never delved into the whole mythology and ideology underlying it. Which I guess makes me a careless parent. Ooops.
I would join them to watch Adventure Time, and Regular Show in particular as they appealed to me in narrative terms, but they never seemed particularly gripped by Steven Universe.
They're past that age now, but you've piqued my interest and I may have to check it out myself, as there's clearly much more than initially met the eye as I was passing through the TV room and glancing at the screen.