Klopp, Pep, Mourinho, Conte, Allegri, Jardim. None of them coming to Barca lol. Not Barca DNA. Neither will the likes of Setien, Marcelino or Montella.
There is a problem here, with this Barca DNA. A lot of managers do not have an unique style of their own, but know the art of versatility and flexibility, managing to adjust their approach based on the team's needs and it's strenghts. Great managers do that, in fact I'd call it the no1 asset of a great manager -- knowing how to set up up their team according with it's strenghts and weaknesses.
So, for example, how do we know that Allegri won't manage to make Barcelona play great football, if we don't give him the job?
If a great manager will come at Barcelona, it's not like he'll make a defensive team out of us. The players and the club's culture determine how the team plays generally (I'm speaking more in a broader sense), and any top manager would be crazy to go against it. It's the details that are different from manager to manager.
Take Lucho and Guardiola. Tactics are very different. But we still play in a way that is recognizable as Barca football.