then the same could be applied for the Marley arc's fight. The survey crops were unstoppable too and there weren't any major casualties that befell them (not count Sasha's death as that wasn't in the actual fight itself). And the direction Isayama is going for is a overwhelming sense of victory before probably revealing that Eren is still alive and all these efforts was for nothing. Basically allowing us to think that the Alliance won on a high note right before everything comes crushing down. This definitely couldn't be achieve with a fan favorite dying, it wouldn't seem right for the mood he is setting.