Lets face it, Aya is just OP. So I have a solution.
The reason she's so op is because she has the speed of the scout and the strength of saxton hale. This is a recipe for disaster. Plus, touhou was based on bullet hell, not melee. Here's where the change comes in. Instead of a powerful melee attack, she can be given a ranged attack with a righteous bison style ammo meter. Her attack lets her spam powerful projectile attacks, but it quickly chews up ammo, and the ammo meter takes a long time to recharge. When she rages, however, she'll not only go fast, but she can spam all she wants until her rage runs out. This fully simulates her "Illusionary Dominance" spellcard.