Especially since in a 4-3-3 the right and left backs do a lot to support the offense. They need to be able to get up and back, attack and defend. I don't think that's the case at the moment, however much wishful thinking you want to use.
And I think Pouslen and Tiago are kind of a waste of salary. Though both have played well at times. Juve ought to upgrade one of them, purchase a rb or lb(best available), and invest in a CB for when Legro finally runs out of steam. Giovinco is more than capable as an understudy to DP. In a 4-3-3, replacement of Nedved is not an immediate requirement, though it is if Ranieri decides to play a 4-4-2.