The only good thing about Paraguay's national team in the 2010 World Cup and 2011 Copa America was Larissa Riquelme. They were cynical, defensive, and in 2011 played some of the worst negative football I have ever seen. And the coach then was the Argentine Gerardo Martino, who has recently been appointed as coach for FC Barcelona.
Looking at Mr. Martino's CV there are some explanations to his appointment: he is a pupil of Marcelo Bielsa, who also inspired Pep Guardiola to the pressuring and offensive football that he refined in FC Barcelona. In fact, upon his return to Argentina's Newell's Old Boys after his stint in Paraguay, he was highly critical of what he called Argentine's football modern tendency to want to win rather than entertain.
At the same time he has shown, particularly in Paraguay, that he is able to be more cynical given the situation where he did not have the players to play like he liked. In Barcelona he will be able to, but there can be little doubt that he will also give Barcelona more cynicism, maybe like they needed against Bayern Munich in this year's Champions League.
No matter what, it will be very interesting to see how he does.