Having all three sides of stormrush attacks being undodgeable is cool in all but it might be better to have more options.

My suggestion,

Top direction should still be undodgeable

Left direction have hyper armor but perhaps should have slightly slower attack speed to balance.

Right direction should be a speed attack, the fastest of all three attacks. Meant to intercept opponents in between attacks or quickly land an opening blow.

This way your opponent will have to consider more than just interrupting the stormrush with an attack or attempting to block it.