the man who coached him would have a very versatile opinion on what the player can and cannot do, and what his current capabilities are. miha allegedly wants him.
so i could also ask you the opposite; what kinda guarantees you have that he won't be a stable defender for the next 15 years?
Guarantees? I have statistics, plenty of players are hyped when they are young but very few actually become top players.
Not going farther than Milan, you had Balotelli, Pato, Gourcuff, Mexes that was a super-hyped young defender that got Roma in trouble with his transfer, Yanga-Mbiwa that we wanted to get from Montpellier (and he was playing in NT) that sucked afterwards, Astori that can't make the quality jump, De Sciglio that has been lost for the last season and a half (Seedorf even saying he shouldn't play on the left), El Shaarawy scored 16 goals in half a season and now we want to give him away for 14mill, and I'm not sure if there are any decent offers despite the fact that I still believe he can make it.
You even have grown up players that play good one season and fuck up the next, it's called being inconsistent.
As about coaches and players, a coach can give an opinion but in the end, it's the player that has to play and adapt to the new team. Look at Pochetino and Osvaldo, things were peachy in Espanyol ... then when he brought him to Southampton, Osvaldo sucked. Allegri and Matri is another example, solid play at Cagliari and Juve, sucked at Milan.
Long story short, if we spend 20 mill, we're buying him as a top player, and the truth is that he currently isn't, hence it's a gamble. Can you say that he's an upgrade over our current defenders. Yepes in 2014 played 25 games with Atalanta, but that doesn't make him a top player.
Either way I don't wanna argue with you, I'm just voicing my concerns. For the sake of Milan I hope I'm wrong, even though I've been more times right than wrong.