I believe JT & Cahill are better defenders than Luiz. As you said, we prefer various styles. When Luiz goes on the attack, mid-fielders are looking at him flying by. If he makes mistake, the ball is taken away from him, a quick counter-attack follows & Luiz is adjusting his shorts in the nowhere land. Personally, I do not even like to see him taking a long distance free kicks. Short ones, let him have it though. Most of the times, he kicks the ball into Jesus´ land.