Hikari Karibuchi, is a much deeper character, and is a much more interesting protagonist, than Miyafuji. The Neuroi too were such a step-up from the past seasons, it's great seeing the witches have to use their brains to take out the neuroi.
Hikari Karibuchi's magic struggle no doubt made Brave Witches very compelling to watch as a story.
Plus the neuroi became smarter, making the battle scenes give me the same hype akin to good shounen fight scenes.
Brave Witches is not "meh," and it is much more than just a "spinoff." The flawed but hardworking 502nd Brave Witches should have its own franchise, a foil to Strike Witches' super-aces that never fail.