Cuadrado's signing was more important, it gives us a lot of options.
It is true though that we are in critic situation at the midfield, with 2 shit players (Hernanes & Sturaro), 1 very important player with a very serious injury (Marchisio), 2 players very very injury prone (Asamoah & Khedira), 1 project player who will take time to develop even though there's talent (Lemina) and Pjanic, who we still have to see how he fits and who is somewhat fragile to knocks and etc.
At this point, even selling Pereyra for peanuts (13M in 4 yrs = little more than 3M a year is peanuts today) looks bad. We must be very lucky with injuries this first semester and Allegri will have to rotate these guys hard.
On the other hand, Witsel doesn't convince me and the guy is pretty expensive for a backup player (come on, 4M salaries and 18/20M fee? Wtf?).
And I think Sandro, Cuadrado and Pjaca may really work out as CMs, even though I wouldn't like to see Sandro there because Evra has absolutely no condition to play as a winger at this point.
Anyway, I definitely see Marotta buying him for around 8M in january.