I know a lot of people are very interested to see how Barcelona is going to perform in the Champions League competition. I honestly do not think that we should have big expectations from Barcelona. Personally, I do not think Barcelona will go very far in the Champions League. In my personal opinion if Barcelona can actually reach the semi-final of the Champions League I will say that it is going to be a decent performance from Barcelona.
I also understand that you are trying to say Robert Levendoski and İlkay Gündoğan have lifted the Champions League trophy before. But they are quite old right now. So I cannot say that Barcelona is going to win the Champions League trophy because they are in the squad.
Barcelona improved a lot since Xavi started training the team and since Lewandowski joined them also. The old players have left the club, yet the impact of their departure was absorbed swiftly. It is true they couldn't do much in European competitions but they dominated by far La Liga. Their defencive line was one of the best in Europe. That transition period wasn't very successful but it is going smoothly to the better.
Barcelona problem remained the money, otherwise I expect them to play in Champions League finals next season, maybe they will not lift it but at least they will not humiliate themselves this time.