It doesn't change the premisenof the tournament. Other big nations only take non established national team players. Italy took Rocchi, for instant.
Thats what i dont like
Look, do you watch these U21 / U23 tournaments ? I tend to watch some game now and then. Its usually awfull, because the games are restless and technically poor.
Now, take 3 experienced stars and 8 youngsters. They add experience, calm and balance to the team, and leadership. Suddenly you get all this talent beeing exciting, and supported by experienced players
Italy with Bonucci, Marchisio and Motta. Verratti as a U23. ALl the others beeing just U23.
Brazil with Neymar, T. Silva, and some midfielder
Germany with Hummels, Khedira and Neuer
Argentina with Mascherano, Messi and some defender
etc
Look. All these u23 players now are supported by a few stars.Great experience for them. And in each game, they play against 3 other stars
I would soooo watch that. And it would be an excellent experience with the seniors for the youngsters