That's why he has gone to another club. When is the time right? Not right now, when we have the best defensive record in the league and are unbeaten. Team first, players second.
I think you missed the point that I agree with the ideal, but we probably disagree how often young players should be involved with this Juventus. It's an idealistic approach, but young players make mistakes all the time simply because they don't have that maturity and knowledge to know how to deal with all situations, particularly pressure ones. Take a look at Savic at Man City. Sure, he has good attributes but he is making elementary mistakes all the time, costing goals and potentially points. So where do you draw the line? 1, 3, 5, 11 young players? Considering where Juventus have come from the last two seasons (7th, 7th), it is to be expected that we go for ready made players. And it's working. We missed the boat in 06-07 to blood several young players, we aren't an Udinese who can afford to let young players play for 2-3 seasons and make their mistakes here, let them do it and grow elsewhere.
Man Utd have had Ferguson for 25 years, we don't have that winning mentality, total focus on young players and record to fall back on. He may also not win anything this year with the kids he has. The experienced players continually do the business. If you took another manager and gave them Fergie's current team they would be an inferior unit.
As for Chelsea, have a chat to some of their fans, it has become a running joke how they don't see any of the 'wonderkid' players come through their academy.
For all his potential and attributes, I'm pretty certain we wouldn't be unbeaten or top of the league if Sorensen played all of Bonucci's games this season. Sorensen can be a cracking player but he has a good opportunity now to play more and iron out mistakes somewhere where they count less.
As for Bonucci, he's a player with some good attributes (confidence, calmness, aerial strength), and some bad ones (body positioning, penchant for aimless long passes, lack of pace). His calmness shouldn't be underestimated simply because of his bad attributes, nor should our defensive record. Still, I'd prefer someone else long term, and right now it isn't Sorensen.