I don't want to go into analysis that who was at fault for his departure but I am pretty sure that we missed on something special. He has played a lot in a midfield which I think is better than us, in a team that is about the same reputation and history of us, and until now has done brilliantly and paid Conte his trust.
Anyway, we had better players which left or we missed on them. Di Stefano, Puskas, Ronaldinho were all done deals and yet here we are. But, personally I am very interested to see how his career progresses cause I think that he has potential to become one of the best midfielders in the world. The only question is if he will be patient (or more importantly will Raiola not be a cnut) to achieve it on Juve learning from Pirlo and co or will he become new Zlatan changing clubs every year so his agent gets a ton of money from him.