As a fan of Sasha her death was an untimely blow, considering the fact that I had semester exams in two days. It crippled me, I hated the fact and couldn’t accept it. But I gave it a thought and here’s what I personally think. Sasha was a character who was very well developed and had enough screen time, whereas Connie( it was either her or Connie) was never developed. Also, Gabi and Jean will be getting enough development since Sasha’s no more.
The only plausible answer I was able to come up with was the fact that Sasha didn’t have a major part in Isayama’s long term goal, hence he decided to chuck her off.
This is my personal opinion, you’re free to come up with yours. It would be great if you could share it as well, after all we all deserved to be heard.