We have so many midfielders. Matuidi is the last thing we need. Between Marchisio, Pjanic, Khedira, Asamoah: All 3 are starting quality. Then you have depth in Lemina, Sturaro, and Hernanes. Pjaca according to Allegri can also play as a central mid (although I think that is a bad fit). My point is for a 3-5-2, we're fine when healthy. There two real positions we could add. I think one would involve selling Hernanes.
1) A trequartista. That mean James Rodriguez, Christian Eriksen, Medzut Ozil...no exceptions. We can't add a Saponara.
2) A true DM. We don't have a real water carrier. This is a luxury though, and this would certainly involve clearing Hernanes' salary. The ideal player would have been Mascherano or even Kante. Gustavo is an option, but I would only buy if Hernanes was leaving. It is a luxury and not a necessity.
Otherwise, our team is battle ready.