Deflect.
It was a defensive soul skill that was very hard to master, much less execute in real combat.
After all, to successfully execute this technique, wizards needed to hone their senses, reflexes, and the ability to manipulate soul power to the point where they could sense incoming attacks and react by projecting a focused burst of soul power precisely where the attack was going to travel through, essentially intercepting and deflecting the attack before it could reach them.
In simpler words, Deflect was a defensive soul skill that relied heavily on the ability to sense incoming attacks, timing, and an instant yet controlled output of soul power.
If you were too late to sense an incoming attack, your timing was even a little off, or if the amount of soul power was too little to deflect the blow, you would be risking your life.
Thus, in a life-and-death situation, nine out of ten wizards wouldn't rely on it.