Xavi in Barcelona was very impressive and I couldn't expect to see Barcelona winning the La Liga title when he started working there because Xavi is not experienced as other coaches. However, in last season Barcelona couldn't play in the champions league but I think in the next season when they are racing with other teams like Real Madrid and Machester City, they can even have the chance to win the champions league title if we see the same performance from this team in the next season.
If Barcelona's performance is still the same as before next season, it might only be possible for Barcelona to win La Liga again next season. Meanwhile, to win the Champions League next season, of course Barcelona needs to improve its performance next season better than the previous one. Because last season's failure in the Champions League is an example that is still very close for Barcelona to see it and try to make improvements before they go into next season.