Consider doing this "Moneyball" experiment using Football Manager [1] games. Those games are made for soccer/football management simulation. And your "Moneyball" kind of playthrough is called LLM (Lower League Management) in the FM community.
The number of ways I could affect a match was insane. It was great to understand the game and second guess how to beat the opponent (which meant studying the opponent's form, tactics, key players, injuries besides your own).
I created excel sheets of players that I would scout and make averages of key attributes (like Pace, Dribbling, Heading, Finishing). These averages decided my player purchase decisions.
With FM2007, I think I took Hull City from being a scrappy team to a team of Real Madrid's caliber within 5 years and then maintained that till season 2018. I could've gone further but memory leaks caused the game to go slow.
I spent years of my childhood playing this. Could I have learned something more productive in that same time period? Yes.
Do I regret studying this game inside out? No way.
To echo the parent poster's comment. It would be very cool to extend this blog into a series and see an analysis like this applied to the most recent version of Football Manager.
I know it's not the same game, and was never as sophisticated as modern FM, but damn it was addictive, even for a non-footy fan. I might have to take a look at modern era FM.
[0]: https://en.wikipedia.org/wiki/Football_Manager_(1982_series)
Presumably the unrealistic part is the how well it is possible to predict who will excel to a world class level.
You take base athleticism and technical ability and you can clearly produce national league quality players very predictably and consistently. One would assume it is more difficult to judge future world-class potential and even more so the likelihood that potential will be lived up to.
Arsenal actually bought StatDNA, a football data analytics company, a couple of years ago. So time will tell how they will use this to their advantage.
In real life, "finding all the Uber Wunderkids who can easily be bought" is actually extremely hard, as there are too many external factors that could determine if a wunderkid becomes a Ronaldo, as demonstrated by several talented athletes that achieved nothing.
Plus, a lot of those factors are hard for an algorithm to "handle", e.g. luck in finding/identifying a wunderkid, getting him motivated and committed, him having enough maturity to work on improving and the psychological resilience to withstand what comes with the job, etc etc...
FIFA EA - Dribbling Ability: 23 (subjective)
Moneyball - On Base Percentage 23% (objective)
http://www.polygon.com/2016/3/6/11169526/ootp-baseball-17-mi...
[1]http://thesetpieces.com/features/football-manager-meets-mone...
FIFA is basically child's play compared to depth of Football Manager where your transfers actually mean something and are in fact hard to pull off - even if you have the budget, often there's no way of attracting recognizable names or any talent at all without a certain level of reputation. I'd consider it a true challenge.