Berardi hasent noticeably got better over those 4 years.
Because he's already been playing on a constant high level in those 4 years, especially considering his age. A level Pjaca has yet to reach, being only one year younger.
I would argue he needs to join a better team to improve even further, and now that we finally play a formation that makes use of wingers, i'm confident he'll do so in summer.
Are you really mad at a young winger because he wasn't overly eager to join a team that used to play 352? Having the Coman case right in front of his nose?
He was 20/21 and had (and still has) plenty of time to grow, nothing wrong in staying another year at Sass, plaing in europe with your team, and waiting how things turn out at Juventus, formation wise. Looking at how things stand it was the right thing to do.