I agree with you, Barcelona won the last season La liga beating even stronger team's like Real Madrid to top the league, which was a good performance and to keep to that trends, there is a need to further ride on the record and performance better than the last season, but truly this season, Barcelona have not really shown any level pf consistency in their performance and in the last few matches, it has become clear that the club is struggling in this season much more than the last season when their we're able to win the league title.
Most of the time, is either they play draw game or even lose to their opponents in this season.
The word consistency have practiced by Girona and Real Madrid this season, exclude Barcelona and Atletico Madrid who are struggling in matches. Xavi Hernandez having no change in his game pattern, he keep repeating his strategy and his opponents have noticed his formulation and they have implement strategies to stop him and his team from more games than usual. Barcelona won the league title last season but this is new season, is different and alot of actions have taken place.