I like Marquez... but I don't see giving up Tiago as necessary to acquire him.
Given a couple more chances, I think Tiago could really thrive at Juve. He and Iaquinta changed the whole Parma game themselves, and that is what Ranieri should be encouraging. Camoranesi needs some help in the midfield creativity department, and as much as I like Palladino, I don't think his passes are in the same league as Tiago or Camoranesi.
Toss Almiron for Cigarini, money, or a bag of Nike T90 footballs, or anything... but give Tiago a real chance until June.
On the other hand, its tough to say Marquez or Zambrotta (the likely exchanges from Barca) wouldn't be nice... they'd bestow instant credibility to the defense, which would be compounded by Andrade's return in Feb/Mar.