On paper, it was a success. However, looking at the performances of the team; it was a failure in some ways. If it weren't for Messi putting the team on his back; it would have been a complete failure of a season. If Messi had been injured for about 4 months....3rd or 4th place in La Liga is not unreasonable and a definite Champions League exit at the round of 16.
Let's face it, guys. Barcelona were often abysmal when Messi didn't play or until he bailed them out. Xavi declined a lot this season(except a few matches), Alexis didn't start playing decently well until the last month, Pedro was awful, Pique and Alves were inconsistent, Busquets suffered, Fabregas suffered, Puyol always hurt, etc.
Some people are excusing Tito but I won't do the same. He often made horrible substitutions or no substitutions at all. I can't even count the amount of times he waited until the last 10 minutes to bring on Villa in a match where he should have been brought on way sooner. He didn't give Thiago, Montoya, Bartra, or especially Tello enough minutes when they clearly deserved them. Does Tito hate youth? Everyone was hoping for Tello against Bayern and he didn't even make the subs. Tito's tactics were also very poor at times aside from the Milan 2nd leg. He should have started a double pivot in the first leg vs Bayern and even when he saw things were going poorly he didn't do ANYTHING. Could have made changes at halftime when it was only 1-0 and Barcelona could have had a good result with even a 2-1 loss but nope.
In conclusion, winning La Liga is great but I'm more disappointed in the way the team played in big matches and how they got horribly embarrassed in the Champions League(only even made the semis thanks to Messi) than I am happy about La Liga.