Funny you say that because he is one of the main reasons that Barca dominated the way they did. I remmeber Spanish media were complaining and saying Iniesta and Xavi couldn't play together. What position did Barca finish before Pep? They had to play a play off to get into the CL ffs. Xavi was about to leave, Messi was injured every 3 months, Pedro and Busquets where playing in third tier, Pique was a sub on our bench, Ronaldinho was the main man in the team stil etc
If any other manager walked into that team the Barcelona we know would simply never have been assembled. Imagine if they went with Mou. He would play a double pivote with Yaya and Keita, Busquets and Pedro would probably have been sold to some 2nd division side and Messi will still be getting injured every 5 months. Xavi would have left because he wouldn't want to play rugby under Mou and Alves would mostly likely never have gone to Barca. The team would be nowhere be as regarded as it is today.
Saying he just walked into the best team is an utter myth. The way they played and dominated as we've seen from City in the EPL has a lot to do with his coaching.
You also said City can get whoever they want, Sanchez, Jorghino Fred, Dani Alves, Mbappe all tell a different story. They have spent like 50/60 mill net more than us and before he came, they came 4th on goal difference! If we didn't fade away He should have been coaching in the Europa League.