Barza hasnt been too bad. But Chivu just looks that much better on the other side. He is having a good ole battle with Amauri, and at this stage Chivu is coming out on top (though he taking a note out old trick number 1: if opposition is stronger than you just foul him

).
I rate Spalletti as a coach. At early on, Palermo mid was getting on top of Roman defence, and thus enjoying large share of possession. So he rightly adjusts and push his forward a bit more, and ask them to close down Palermo defenders a bit quicker. Palermo whilst generally technically proficient throughout the team, doesnt have 4 defenders who are comfortable on the ball. I think this is where Roma is winning their game ATM.