I think like Zhixin that there are various logical reasons for the move:
1. Inconsistancy:
Olivera is known for that, regardless of the bright talent he posses, his loan will only give him more guarentee of first team appearance which is good for him. on the other hand...
2. Experience/Guarantee:
Juve need to assure themselves that they will only play 1 season at most! in serie B. Anything more will be fatally damaging for the club. The club isn't taking anychances on shinning youngsters, they will build a club with enough experience and conistancy to immediately command serie B.
Aside from the two reasons, we really do have enough coverage, we've got Nedved, Marchionni.....and it looks like we're looking to sign a midfielder, preferable with attacking capabilities.
As for cover, Kapo is less explosive but looks more consistant, Palladino can be played as a left winger. Guzman and Paro can also be played in those positions to some extent.
At the momment I still trust DD's abilities. I'd like to see in the Bira Moretti cup of what kind of line-up and formation we will be using. Then we can discuss further about who we need.