Dybala has been super impressive this season, while Berardi has disappointed a lot. Zaza has improved to last season but still nowhere near what Dybala has done this season. They're all very talented but I must say Dybala has a leap to both Berardi and Zaza in terms of quality. He's a more complete player and his primary abilities are beyond those of Zaza and maybe Berardi too.
We should do everything we can to sign Dybala and then evaluate the options of Berardi and Zaza. If we cannot give Berardi or Zaza more then 15 games a season I don't think bringing them back is a great idea. Berardi is best at RF/RW (433) or AMR (4231), but can also slot in at ST in Allegri's 4312 similar to the way Coman has been used here. That said, I think having both Coman and Berardi in the squad for a potential 433 formation is a waste of everybodys time. We'd ensure surprising formation options but neither Coman nor Berardi would play enough of this system to develop the with the right pace. This is, if we have Tevez, Morata, Dybala and Zaza(or another 4th ST) in the team already. Hence 90% games played 4312 system.
For the 4312 system we'd need 4 ST and 2 AM.
I don't understand why Coman isn't played at AM when introduced instead of ST. This falls down on whether we'll sign an AM upgrade to Pereyra as well. And I don't think Dybala can play AM. CF and AM is completely different roles and Dybala wouldn't want to play there.