Three things are certain next year at AC Milan...the Team WILL concede goals, the Team will NOT go undefeated and Nigel De Jong will start in midfield. One less thing Filippo Inzaghi has to worry about is who starts in the center of the park and while in my opinion it was a no brainer there was still a belief that that spot was reserved for Ricardo Montolivo.
Had this team been built differently, with a bit more balance, one could argue you could afford to play Montolivo in a holding role flanked by a combination of Muntari, De Jong, and Poli. The problem is this team is built to attack in a mediocre fashion and has the balance of a one legged man on a pogo stick. This team needs all the strength and steel in can get in the spine and with De Jong being arguably Milan's most consistent performer last season then you have to give the guy the nod. His partners are a bit more debate and right now it looks like a mix of Sulley Muntari, Andrea Poli, Bryan Cristante and Ricardo Saponara which begs the question what happens to Montolivo when he comes back from injury? The 4-3-3 requires a bit very specific skill set in midfield and the need for someone to distribute from deep is not a huge necessity. In fact one can argue that your passing from back to front should be of the 5-10 meter variety and you let your attacking trio create both play and space so box to box midfielders can explode into channels and score goals. The problem with this outside of Poli the team lacks that tenacious runner, so much like the rest of Milan the personnel don't fit the tactics! A separate conversation for a different day.
At the end of the day I imagine Inzaghi will tailor the midfield to the opponent and expect them to hold as a compact unit when needed and expand into a trident when the opponent allows it. Will this team be capable of that flexibility, early signs say no, but there is time to grow and learn to evolve as a group.