I really enjoyed reading your review, it's very well structured and fairly describes everything about the movie.

Although I'm not really a fan of Slam Dunk (not because it's bad, it's just not my cup of tea), I must admit that this movie really caught my attention because of the animation style. It looks nice and different from usual. But you're absolutely right pointing out that that aspect is not enough for considering it a good movie. Visuals are the most striking part, but if the story has no depth or good narrative, then it's basically a waste