We can't judge Barcelona like this, we know Xavi is a great coach but we can't forget that Barcelona has many financial issues and this team couldn't buy the players Xavi needs to have. In fact, even if Xavi is the best coach in the world still he needs better players, I think that's why they lost the El Classico game recently against Real Madrid in La Liga.
Just let xavi to proves his capability in the UCL first. It is too early to call him as the best coach in the world. I think that if we have seen that he was always failed in bringing barcelona to the quarter or semifinal. I don't put a very big expectation toward him at this moment.
People shall need to let him try to give proof if he was able changing barcelona to be even better than before. Barcelona was always strong in la liga but it was weak in the UCL. Wnning the group stage does not guarantee barcelona to go to the further stage easily.
People are always calling him as the best coach in the world which doesn't even make sense. Xavi is nothing than average coach that was helping the club to win the domestic competition.
The coach like ancellotti which can be called as the best coach as he had been winning so many trophies in various competitions. It's too early to call xavi as a world class coach.