Xabi seems to adjust the formation used with the available players. Xabi in Leverkusen more often uses 3 defenders and 4 midfielders, which makes Leverkusen's type of game with dominant ball possession.
But it seems a different pattern is applied to Madrid, who have stronger players in the attacking game pattern. We have not seen how effective Xabi's method will be applied for next season. But hopefully, there will be no problems with the players and the playing style designed by Xabi.
So after Barcelona had had so many disastrous seasons, he came, if i am not mistaken, Xabi and convinced the management to go into debt to rebuild the team and it worked, if i am not mistaken, even if partially.
I think he has a good vision although maybe Flick is better
Not Xabi, my friend, but Xavi Hernandez. He is a Barcelona legend. He also took Barcelona to a higher level as a technical director. Today, everyone congratulates Flick, who replaced him, but Xavi is the person who best transferred La Masia to Barcelona's main squad. Before his management, Barcelona was under the impression of being a mediocre team, but he made many changes as soon as he came to the team. He brought very important players from the youth academy to Barcelona, which was going through financially difficult times. Thanks to this, they also won the championship. Flick created today's Barcelona with a few touches on the team he left behind. In other words, in my opinion, Xavi is the architect of Barcelona.