Regarding Satoko, she generally was the least popular main cast member in Japan, which is probably why they had courage to do something so extreme with her that basically changes the entire focus of her character (and it seems to have worked popularity-wise). I'm looking forward to how the manga handles her transition though since so far it has been better in using elements of the original that aren't relevant to Gou/Sotsu's plot just for consistency.
The director outright talked about using over the top violence to diminish its impact, making it more like a joke. So, yes, it was on purpose, although the "purpose" itself seems kind of misguided. I guess it might be because the violence is often against minors? Rina's death was one of the few that seemed to be played completely straight. Although Teppei's death still was a joke...
https://febri.jp/topics/higurashianime_director_interview/
I'm starting to think that maybe R07's outline didn't have actual arc by arc answer arcs, just a quick overview of what Satoko did, and then the anime staff decided to expand that into answer arcs, but completely failed to do anything with that expansion. That would explain why the arcs oddly barely seem to fill in Gou's original elements, and don't even really give much character development to Satoko, aside from slowly introducing the witch elements. The actual answers often being simplistic or just outright skipped. If I'm right about this at least it'd meant the manga would have a lot of potential to do better answers, since it wouldn't be tied to the oddities of the anime.
Some quotes about the writing process of Gou/Sotsu
https://febri.jp/topics/higurashianime_director_interview/
On March 23, 2021, the website Febri posted an interview with Ryukishi07 regarding Higurashi: When They Cry - GOU. Interview is translated by rockmor. This is the first Higurashi anime series in about seven years, how did it all start? Ryukishi07: Once, when I was drinking tea with people in the...
07th-expansion.fandom.com
He mentions that the plot originally wasn't designed with animation in mind, before going through the anime staff, but the whole structure of Sotsu seems designed to have been written to be able to reuse animation from Gou...