IMO the Great Man has done 3 mistakes in an otherwise fantastic work here at Juve:
1) Not sealing the deal with Pescara and Verratti quickly.
2) Selling Vidal for being a drunk.
3) Letting go Dani Alves without a proper replacement.
Jorge Martinez, Hernanes, Isla, endless loans of Melo to get no money, underselling Vidal, underselling Bonucci, selling Bonucci to a rival, underselling Tevez, underselling Dani Alves, underselling Llorente, agents fees on Pogba.....
I have a feeling missing on Schick and Keita, spending a huge chunk of our budget on Benatia could be on that list eventually.
Marotta has done an excellent job overall but he certainly has more than 3 mistakes.