Just curious but how can you make this judgment when you've never seen him play as a CB? Just because you "don't like the idea?"
Canna is slow as shit and gets exposed every time he goes up against some who has decent pace. That's one of our main problems with our defense - getting exposed by speedy players. To say his aerial ability is limited lets me know you've never really seen this guy play aside from the handful of appearances he's made at RB for us. He's actually quite good in the air.
If I could draw you a Venn diagram with the ideal characteristics of a centre-back, I'd probably present three circles from which you'd have to choose two. They'd be labelled "pace", "reading of the game" and "physical presence/aerial ability".
I'm glad you mentioned Cannavaro, because what he lacks in pace he makes up for with the other two characteristics in abundance.
You're correct in saying that the only times I've seen Caceres play were in a Juve shirt, but for what it's worth I've watched every match we've played this season, and because I happen to
like Caceres and wish for him to become a world-class defender, I keep a keen eye on him every time he's presented with an opportunity to show us something. You're right; I'm probably being harsh on him by saying that his aerial ability is limited, and it was coming off the back of his lacklustre defending against Bordeaux.
All things considered, you definitely make a point and it's probably not fair for me to judge Caceres based on the few times he's played at RB, especially considering his preferred position is CB.
That said, as I mentioned before I think we're lacking more in the wingback department than CB, and I'd like to see Caceres' pace and attacking instinct nurtured to make him a quality RB.