I wouldnt mind that but as said dont see how thats sustainable with this midfield, it was barely so when we had Pogba and Pereyra, now less so IMO.
Flexibility in big CL nights is one thing, but I dont think the solution is changing from 3-5-2 at all full time, but player selection and how he adjusts tactically to how our midfield quality is weakened (you lose tons of physicality and ability without Pogba, and lots of tactical organisation and controlling presence without Marchisio). Frankly speaking our squad is completely built for this formation almost solely, our best players we signed with it in mind, only alternative realistic alternative to is what you suggest 4-3-1-2 because only change for that is one CB less and more more midfielder.
While people who suggest 4-3-3 and even more unrealistic 4-2-3-1 one simply refuse to face the reality of this squad. We have 2 wingers in whole squad so lets play a formation that uses 2 all the time. We have 2 world class forwards in Higauin and Dybala so lets play a formation that only uses 1 of them? We have a weaker CM midfield so lets play 4-2-3-1 that weakens its number even more? Thats assuming you will play Pjanic as one of two, which would be fragile. Playing him as AM is essentially 3 man midfield, and would again have the silly idea and conundrum of benching Dybala or Higauin.