With Lewandowski gone, he will be Dortmund's starting center forward. From his perspective, he would rather be Dortmund's starting center forward in the champions league than go back to Juve where he may not even be 2nd choice. He is probably deep down dissapointed with Juve's lack of commitment.
I mean, if you look at our squad today, only Marchisio and Giovinco are homegrown and Giovinco was sold and bought back.
The Giovinco "dissapointment" should not dictate our attitude to other youth developments.
I for one, hope that players like Berardi get a chance to come into Juve EARLY and prove their worth before being sold to other clubs.