Barcelona has all it takes to do well in the Champions league. Inter got to the champions league final, is Inter a better team than Barcelona, when you compare their players?
The players and managers matter, but it takes more than just a good squad to do well in Europe. If you want to succeed in Europe you have to know how to win games. Win games even in times when you don't play really well. It can't be every game that a team will play well. So if you're able to win your games in matches that you didn't play very well then you are safe. That is the edge Madrid has over other teams in that competition. Madrid can win games when they don't play well.
Next season will be good for Barcelona because they're rebuilding and and the process is going well. If they are not unlucky like they were last season with injuries and bad officiating they might do well.