Are any of those 4 World Champions?
I rest my case.
I have rated chiellini as world class for a few years now. Bonucci has very little experience in the top flight, and was fucked up by every game that Motta played next to him and every game that Grosso played next to Chiellini. Lugano??? He is a natural born leader, a history of winning, a history of gaining respect from team-mates and fans alike wherever he has played, and recently was voted the best captain at the coppa america...yes, i think he brings something world class. Alex??? a decent, dependable player, but hardly a massive improvement over Bonucci...
So, really, what is your point, or your 'case' as you put it?
Chiellini next to bonucci, with lich and ziegler/ de ceglie, will be fine. Swap bonucci for lugano or alex, and we are even more solid...