I know people like him, and had high hopes for him after his youth career, but he certainly never fulfilled that promise. He's not crap, but he's certainly not an elite player and never has been. Not for Italy. Not for Juventus. Not even really for Parma.
I mean Dybala had basically the same season as Gio had at Parma, with 13 goals 10 assists, as opposed to Gio with 15 goals 11 assists. But Dybala did it at 21 whereas Gio didn't do it until 25. He's just another one season wonder player, who should probably have stayed at a mid-table club and been a very good player there. He's just not good enough for a top club.
And he's not tearing up MLS like the Messi of the league. He has 21 goals-12 assists in 30 games there. Messi and Ronaldo have had seasons where they score 40 goals in 30 games.