Why do you doubt Paul Pogba performance at the Juvents club?
Even though Paul Pogba is also an important role at this club and his contribution to Juvents is also very good even though it sometime look inconsistent but in reality he was able to appear solid with other player who were able to bring Juvents to a conference league ticket.
I know that even though Juvents still have problem with offense but that is not a problem for Juvents to get up next season and still need senior player in it to be able to appear stronger and get the title they want, such as the champions league.
In addition, this new player, as you said, will strengthen the performance of the Juvents club to continue to try to get the best position in the standings and regarding the news that Vlahovic will leave Juventus, this is not true because he is still under contract with Juvents for the next 3 year.
So in essence Juventus in the next season will give a strong performance and prove to the whole world that Juvent can rise from this adversity.
In the past yeah, Pogba made a great contribution to Juventus. But I mean the seasons from 2012/13 to 2015/16. Other than that Pogba has done nothing since he joined the team back after leaving Manchester United. He played in only 10 games in total in which he didn't even play properly last season.
In this situation I think that it is quite risky for Juventus to give him another chance. He can get a lasting injury once again during the season and it would mean nothing to keep him in the squad. There is no guarantee for that maybe but I'm still doubtful about that.