Robert Kovac wasn't a joker though. When he partnered Lucio, he'd have to save his ass all the time. It was a joke watching Lucio being bailed out time and time again like in the matches against Chelsea several years ago, or the Micoud days with Bremen. Yet Robert couldn't save him all the time, and they suffered for it.
I believe you're giving him too much credit for a very well organized Mourinho defense. Lucio made mistakes against Barca and even in the final against Bayern.
Mourinho said loud and clear why he insisted Lucio to be bought. He wanted him because Lucio can play the ball and is great in taking the ball out of the box. Of course, he had Lucio's defensive qualities in mind too, but he wasn't looking strictly for amazing defensive qualities. Mourinho had a vision how he would like the defense to look and he implemented it.
What I'm saying is that sometimes, and I underline
sometimes, the better player (in this case: the better defender) won't do a better job than the worse defender and the coaches should always look at the defense as a unit. A great defender and a bully, like Chiellini, would have made Inter's defense worse than Lucio, who is worse in defense than Giorgio (IMO).
You are right that sometimes the unit makes the individual much better than he is and Osman is correct too when he says that the unit can make the individual look much worse than he is. But it's a simplification to look at a player like Lucio as a "great defender" or "bad defender".
Personally, I think that Juve desperately needed a Lucio kind of player last year and even in the pre-Calciopoli seasons.