To everyone wanting to sign Sanchez, that will almost surely mean a switch to a 4-3-3 as I don't see Allegri relying on a real 4-2-3-1 with 3 guys playing as strikers for most of our games. Mandzukic is playing as a pure LM and he offers a lot of balance with Cuadrado being the winger he is.
If we do switch to the 4-3-3 then we are moving Dybala away from his preferred position, is it really worth it? it could be. But then signing Sanchez means benching both Mandzukic and Cuadrado. Cuadrado on the bench means Pjaca is even more of a sub. We also need to start another CM, it seems like we can get Tolisso so he is there, but to play with 3 CMs we'll need another quality back up (Bentnacur?).
It might be smarter to first use that money to try and get Bernardeschi who's best role is LW and who can also give Dybala a rest, and stick to the 4-4-2 we have going on. That way we keep a good thing going and don't need to spend so much to make our team work again.
tldr: Singing Sanchez (who I'm a huge fan off) brings a lot reshuffling and market activity. It high risk-high reward in terms of everything needed to make it work.