Actually one of our main issues is that midfield IS weaker, and thats certainly the responsbility of the guy who decides who goes and comes to the club, no? Allegri having no clue is big part of it. But having no fight to win possession or playmaking or reference point in midfield to keep and maintain possession adds alot to the kind of pressure we get on us, and as consequence conceads goals for.
Is it that much weaker? A fit Khedira for Vidal is a slight downgrade no doubt. But Khedira is no shmuck defensively. And IIRC we haven't lost with Khedira-Marchisio-Pogba starting together. Defensively it's not that much weaker and in terms of not having that reference point in Pirlo, it was the conventional wisdom last season that Marchisio made for a better holding mid than Pirlo. We played best last season with Vidal - Marchisio - Pogba with Pereyra in the hole. So there is one real change in the possible starting line up and it doesn't look all that much weaker considering Vidal was so bad for so long last season.
The difference between last season and this one was the certainty in the 4-3-1-2. It's not the personnel but that lack of continuity in formation and line up due to injuries or Allegri's indecision that's made this team play with such a lack of conviction.
I admit, Marotta not buying a trequartista and loaning Cuadrado is partially to blame for that but we didn't have a trequartista last season either. Allegri doesn't have to play Cuadrado if it means playing in a 3-5-2 or 4-3-3 that throws this team completely out of it's comfort zone. Cuadrado has become so important to Allegri that he's virtually rebuilt this teams attack around him to the detriment of any effective system of play. He ought to insist on playing a 4-3-1-2 with Pereyra (when he's fit) in the hole again like last season if that's what brings this side the most balance. Either Cuadrado can somehow fit into that system or he can go back to Chelsea. He's only scored one goal in all the time he's played. If the market really means nothing to Allegri's choices then he wouldn't appease Marotta by building our attack around Cuadrado and wasting Morata out of position.
The amount of injuries in midfield in conjunction with all the new players is also an unprecedented factor that cannot be ignored. That has undoubtedly contributed to this lack of continuity which is neither Marotta nor Allegri's fault.