When Shuri said he "slice as if gently stroking the soft parts", I thought that was going to inspire Kuuga to aim for joints and weak spots, since they had said he was fighting using brute strength.
I don't understand how a swordsman who is supposedly as skilled as Kuuga is would be swinging the sword with only his arms; it'd be akin to a boxer only throwing arm punches (if you want to know what that looks like, look up Ronda Rousey's boxing under Edmond Tarverdyan). Just like how boxers learn to throw punches by planting their feet, rotating their hips, turning over they shoulder, etc, I can't help but think a swordsman would have already learned from experience the same things, albeit applied to a sword.