Objectively, the Warriors-style gameplay is great, but it's not for me. Doesn't really lose points there.

What really drops this game's quality IMO are the storylines. Well, except Scarlet Blaze's, that one felt like what the original Three Houses' Crimson Flower route should have been. The others though?

Azure Gleam doesn't really work nearly as well as Azure Moon in Three Houses did. What made that story work so well to me was how well Dimitri's character arc was handled. Here, it's... okay, but I feel like it softened him a bit too much. But that is small potatoes compared the Edelgard getting brainwashed and instantly losing all agency as a villain on that route. Which is kinda dumb regardless on your opinion of her.

Golden Wildfire has Claude be more morally grey, which is a great idea in theory but it flops because his beef with Rhea doesn't work. They just forget to make her do anything evil in this game, yet even DIMITRI, who is her ALLY ON THIS ROUTE still leaves her for dead.

Pretty much the main boons of this game are expanding on some of the worldbuilding that didn't get touched on in Three Houses, and Byleth being an antagonistic force is great, but... yeah after how enjoyable (if a bit rough around the edges) Three Houses' storylines were (except Crimson Flower), this was a huge letdown for me.