If I've learned a lesson in the last decade, is that unless you strive for brilliance and to mark an era, coaching a big club is not rocket science, most of it revolves around caring about your players not feeling miserable and using concepts that most top players could've learned from their coaches if they paid some attention in their 10/15 years of top level football.
People like Luis Enrique winning a treble (after loosening the saddle of the team in January), Zidane, Ancelotti (too lenient in the post-Pep Bayern), Valverde, Pellegrini or even Allegri are more friend than sergeant to their players.
The old guard of tactical maestros with iron discipline have been failing at top gigs lately, beyond Simeone (which has molded the team to his ideals, something not possible for anyone coming to a juggernaut) Mourinho, Benitez, Conte, "Moyes", Van Gaal and maybe others have been at war and underperformed in Europe's biggest clubs after 2010.
At top level, having new ideas, being liked by the squad and knowing the mentality of the new generation of players looks more important than having a wide array of tactical setups and tons of experience while being unable to win the roster to your side. When stars sign for United, Bayern or Madrid they think they're above tracking back like dogs and not enjoying with the ball, that's the same reason why some top quality players have been scarred by Simeone in Atleti, to be a Sergeant you need a roster of 23 soldiers willing to be underdogs, not a bunch of players that thought they could leave a legacy at football while also enjoying being on the pitch.