For me the decline in Barca’s performance over the seasons has been due to no steady replacement for Xavi and Iniesta at the middle of the park. One cannot help but notice their immediate absence and the way Messi could not single handedly carry the team on his back .
However, I believe there will be a turn around for them come next season. Xavi is doing a great work at the team with the crop of young players he his managing.