If it proved that trying to control the direction of each strike consumed more, then William would try to lower the number of strikes he'd control.
For example, if he executed ten strikes or more to stack together using the dark element, then he'd just control two of them to block the path over his enemy.
This would act as a structural anchor, keeping the rest of the chaotic energy focused without the mental strain of micromanaging every single arc.
He wanted to use the entrapping method of the Burning Star technique. And that to make sure his enemy wouldn't have a chance to escape from his incoming attack and end up losing too much or die in the end.
The goal was to create a localised "kill zone" where the laws of physics were rewritten by his will.
Not to mention any foe entrapped in such an attack wouldn't have the ability to fight back; the sheer pressure of the converging elements would pin them down like an insect under a microscope.
