Tactically, Italy needs an alternative-support to Pirlo. Quite frankly, he is the little engine that could; however, if he gets injured Italy is for the wc-consecutive embarrassment of their life. Diamanti in this game showed how average he really is. Youth injection maybe needed plus a proper trequartista next to the forwards.
I think Pirlo can be compensated with a mid of Motta, De Rossi, Montolivo and a movement-player, I´m not saying this is going to be a 100% compensation, but we should get away with it.
Diamanti is creative, but overal he is not good enough, he is a good joker in the last minutes when the pace of the game slows down, therefore I can understand him being called up.
If Italy develops a winger like Camoranesi, 4-3-3 would be nice, such a player would add enough width to alow somebody like giovinco, Balo or Rossi to play on the other wing, but two of them would be to narrow in my opinion.
I think 4-3-1-2 is still the best atm, although we lack a real treq, but better than a 3-5-2 wit ? on the wings.