I agree that the Direct did a poor job of hyping up the game. They really should have shown off some of the more exciting parts of the game.
I'm unfamiliar with this school/academy kind of setting, so I have no opinion on it.
I love how they let you customize your units by choosing their classes and tweaking their focus. I also like that they are keeping the combat arts from Echoes.
Not too worried about the story right now. I'm actually quite happy that it seems to stay away from the overdone plot of country X suddenly invades country Y and prince(ss) Z has to train a bunch of rag-tag misfits to take back their country. All I hope is that it won't be as problematic as Fates' story was.
Biggest issue right now is definitely the character designs. Some of them just look plain dumb, particulary Female Byleth.