>>543542924
The story is very much still about Sensei, the core message of Blue Archive is that it is up to those who come before to care for those who come after. Yes the focus on students youth, growth, mistakes, and learning is a very big part of the story, but all of it fundamentally hinges on the actions of Sensei and what he does to accommodate all of that for it to even occur in the first place. The easiest way to gauge his significance to the story is to just take any chapter and remove all of his actions; what you're left with is a radically different story that often carries a completely different message.