Don't think we need Mata to be honest. Our current team can make due without a pure attacking midfield playmaker. We have a number of offensive talents who can play in variations of a 3-5-2, 4-3-3, 4-3-1-2, albeit not perfectly. However, that CAM in the 4-3-1-2 is hardly a current issue. Marchisio, Vidal, Pereyra, Asamoah, Pogba can all slot in there if we want to play that formation. Coman/Giovinco could probably as well if you're looking for offense, but both are better as LWers. Plus, in Allegri's 4-3-1-2 he has often used a more of a running CAM with technical abilities rather than an elite playmaker. Examples include Kaka, Emanuelsson, and Boateng. Juve definitely have the personnel to compete with the latter two.
More than anything else we need a left footed attacking midfielder/ winger. Ideally that player could play both as a winger and an attacking midfielder. Right now only really Pepe and Pereyra can slot in there effectively. Berardi will be able to play there next year. When I think of ideal players, I look towards versatility. The last player I would want is one who could only play one position in one formation. Mata is kind of like that. He needs to be given a free role, an has to play either as a winger in a Barca-style formation that relies on short passes, or in the whole as a free attacking MF. His one advantage is that he is left-footed. I love players like Vidal, Di Maria, Shaqiri who are not lazy, are versatile, can play multiple positions and play them well. We should clear out some of the less important players to fund this.
Personally I'd like to see the following:
1) Left-footed Winger/ Central Attacking Midfielder - This player should be fast, an adequate playmaker, and technically able. A two footed player would also be a nice luxury. That gives the winger the option to cut inside or go for a cross.
Current Player Comparable: Bale, Rodriguez
Players who could fill this role (in our price range): Shaqiri, Lamela, Quintero (buy him now before he goes up in price), Douglas Costa, Andre Ayew, Max Kruse (less so, but he'd be cheaper).
2) Young pure playmaker - I do thing we should have one in our arsenal, but I don't think it's our biggest need right now, nor do I think Mata is the answer. I think this should be a player who is ~18-19 years old who can become an impact player in a few years.
Current Player Comparable: Wesley Sneijder
Players who can fill this role: Max Meyer, Max Arnold, Roberto Firmino.
3) Attacking Right Back - Lichtsteiner is getting old, and ultimately is a bit offensively challenged. He is a workhorse, very good defensively, and an absolute thorn in the opponents side (huge pest). I like him in a 4-3-3 or a 4-2-2. But in a narrow formation like a 4-3-2-1, 4-3-1-2, or any wingback formation, I think he isn't adequate enough offensively. This player should seamlessly work in a 3-5-2, or as a fullback. Ideally with injuries, he could even play in a 4-4-2.
Current Player Comparable: Maicon in his prime
Players who can fill this role: Danilo, De Sciglio, Darman, Rafael
4) Centerback - We're okay here for the moment. None of the players are Cannavaro, but we have enough that are capable. We're historically spoiled as Italians as far as defenders go. Ogbonna, Bonucci, Caceres, etc. are probably ok on most other teams, but we need to make sure he have truly standout centre backs. I think we need to buy 1-2, with one being in his prime, and another being older. One needs to be a stopper or at least big and strong. Most of our centrebacks are more attacking in some way (Bonucci is a playmaker, Ogbonna runs, Chiellini runs). It's essentially a replacement for Barzagli.
Current player comparable: Vidic in his prime, Materazzi (when he played), Mats Hummels
Examples of players who could fit the role (I mean this loosely because this generation of defenders is flat out ****.
Veteran Role - Godin, Mertesacker, Agger.
Youth Role: We have Rugani, but we should also look at a few of the following:
-Romagnoli (hard to get, but we should try and get the future group of Italian defenders).
-Luca Antei (that guy's stats are amazing, and he played on the U-21.) Last year: Nearly 4 tackles and 4 interceptions per game. Those # are staggering.
-Doria
-Nastasic
are just a few of the names...
5) Other luxuries - We will need a new LB in the next year because Asamoah should not play there, but with Evra it is not a pressing need. Also a GK.
Also any young Italian players who need to be sent out on loan should be sent to Sassuolo. There is one provincial team that is doing it correctly - that is Sassuolo. You can confidently send your Italian youth there and they will play. I would absolutely love to buy Romagnoli from Rome, and send him to Sassuolo on loan with Rugani when Empoli get's relegated. They can give us Antei in return...
See:
http://www.football-italia.net/55608/sassuolo-model-serie-club