Miko's first two non-spells are indeed pretty dumb, just bullets exploding to rings. Symmetric rings. Third one is not bad, you need to move around the solid rings, and the fourth one is fun.
This is the first time he shoved this into a S6 boss, but haven't most non-spells been this way since forever (especially in Extras) ? Modifying a 'base' pattern to make different attacks.
As for her spell cards (and most of the game's), I think they're very fun (although less pretty, but both at the same time is overkill). I like how there's a lot of moving around and you don't have to constantly plant yourself at the bottom anymore. The ... pacing is also wonderfully done. Miko's fight in particular, it starts off with relatively slow attacks, then comes along the faster knives, which is a warm-up for DISCO; DISCO forces you to move quickly around the screen, readying your body for Guse Kannon; after that the speed drops in 17 Articles, but thanks to the previous attack, your reflexes should be sharp enough to deal with the density. This sucker has a staggering amount of health, you feel tired, and so is the boss. She cheats her way out of the seventh spell card, but unable to even spread her wings
probably just some bug, resulting in a weak last resort that has almost zero speed.
... Nah, I'm just overthinking things.