The problem with midfield is numbers. If we sign Can we then have Can, Pjanic, Matuidi and Bentancur as almost certain to stay. Probably staying is also Khedira. If we presume Marchisio

() and Sturaro are leaving (I seriously doubt we'll sell more than two midfielders in one window, pick who you like) that means a 6th midfielder is the one signed and then you're trying to fit 6 into 3 or maybe even 2.
Beppe will say we're covered in midfield, and in terms of numbers he's right. Quality no but it's not a computer game where you throw in a player and some money for an upgrade, 4-5 will simply not be changed.
I'm not convinced we'll even sign another DC if Benatia leaves, Caldara is coming in.