I've stopped from weighing in as I'm a big fan of his, so obviously would love the deal to go through. Want specifically to address the valuation and the hesitance of some members. The price of youth players across the world has skyrocketed for a variety of reasons. Sure, it's a bubble and we could decide, hey veterans are undervalued, let's go that route, but Milan needs lottery tickets and lots of them. There is not one pillar on this club around which to build.
If the club believes that he can unlock his potential, which is one of the best defenders in the world, then 25 M for one of the best defenders is nothing. It's worth the risk. Sure, would be great if that risk were lower, but that's not where the market is.
Remember that potential costs more than results. Optionality is the most desired thing in all global sports at this point.
Look at a player like Marquinos who showed flashes, was sold for something like 32 M euros and has blossomed into one of the best defenders at what, 22?
Romagnoli is the exact type of player Milan should be after. Young players with massive potential who are ready for the next step. Some will falter. Some will remain flat. Some will excel. Risk comes with reward.
You make good points, and I believe that every fan here wants to have young exciting players with potential that become part of the history of the club.
The problem is that
-1- Loyalty these days doesn't exist. This guy has come through the Roma youth teams and right now he's very eager to leave. What makes you think that he will hesitate if a Real, Bayern or a Manchester comes knocking offering him double the salary that he gets here.
-2- The truth is that we don't know the exact potential of Romagnoli, the same way that we don't know the true potential of Cristante, El Shaarawy, De Sciglio, Niang, Saponara, Rodrigo Ely, Calabria, Suso etc. What we know is the hype that our club is surrounding Romagnoli with which is the same hype that we heard for Yanga Mbiwa two years ago when he was at Montpellier and we were about to buy him.
Comparing him with Marquinhos is unfair, Marquinhos was one of the best defenders of the entire Serie A in addition to being 18-19 years old, and was comfortable with the ball at his feet. Romagnoli is considered one of the best prospects but he's not one of the best defenders yet, in fact at Roma currently he's not considered a starter. Being a starter at Sampdoria doesn't mean that you're good enough to be a starter at a bigger club (see Cerci)
These comparisons to Nesta, Marquinhos etc, are just hype and a way to justify a crazy expense.
-3- Our club was never distinguished as a great club at buying young talent and nurturing them to greatness (e.g. Aubameyang, Darmian or Vieira, Davids). To assume that we suddenly became much better at it at a snap of a finger is short-sighted.
If we want to be better at finding young talent, we should first of all create a great scouting system, invest in those youngsters, and even more important, do it gradually. In the same year we brought Jose Mauri, Suso, Calabria, Rodrigo Ely, Donnaruma and Niang... and we want to bring also Romagnoli? That's a lot of youngsters in one year for a team that is not Udinese or Arsenal.
A classic scenario of a overhyped youngster is what happened with Liverpool and Balotelli. They bought him thinking that they had a class player that would be a solid starter, every performance of his was put under the magnifying glass and checked to the minuscule details, they saw him a few games and said "This guy is not great, he's definitely not worth the money that we spent on him". Then it escalated to "This guy is shit, if we play him we are fighting for a draw" then the pressure from the player escalated to the coach "if the coach plays him, the coach knows nothing".
Ask yourself the question: If Zapata played at Sampdoria, would he be an undisputed starter and have a good season?