Mate, your squad is very good defensively but still lacks creativity in the midfield with no cover for Trezeguet in the attack (Bojinov isn't a true striker but he is a second striker). As I think that either Mavuba or Faty can't be burdened with the responsibilities of our attacking midfield. Also Pato is still young and lacks experience, this doesn't mean that I'm against him joining us but he can be a substitute to a world class midfielder for at least two or more seasons.
I've suggested that we have to sell Camoranesi if we are on verge of signing a better winger like Ribery or Quaresma. Both of them have the edge when compared to Camoranesi, they're younger, quicker and versatile.
Canini is a centre defender in Cagliari. He plays for Italy U21 and he plays regularly for the national side since 2004. He is still 21 years old, tall, strong and he maybe a defence leader in the near future. By the way, we are already negotiating him. You can check a lot about him
here.
Regarding Zanetti's issue, I agree with you, we should keep him and also to be placed in the starting lineup regularly. I just want Tacchinardi and Blasi as a cover for him. Both of them played for us plus they still Juve players, this means that we aren't going to pay to land another defensive midfielder.