It has always been so for long. Real Madrid or Barcelona will definitely win the league next season, but we can't tell for sure which of them is the favorite. Barcelona only added one or two players to their squad and the team bond is already there. Unlike, Madrid that has a new coach and needs to understand every player potential so that, he can use them at the appropriate time for the right wings and positions.
As for Barcelona, I think they will remain strong because their tactics and players are the same as last season, even though they have added one or two to their squad for next season. Meanwhile, Real Madrid still needs to make more changes to address their weaknesses. If they can't be strong in La Liga and the Champions League next season, their signings will be wasted. Although I'm confident that Alonso can improve Real Madrid as long as the current Real Madrid players feel comfortable with his tactics.
They season needs to begin we watch Barcelona first 5 games before we know if they will remain very strong like they were last season since they have same players with some added new players in the squad and Real Madrid is also another team to look after because they have a new manager and new players that arrived to tackle the errors of last season, Real Madrid doesn't need any more changes in the team they have a complete team now Xabi Alonso only needs to have a good formation and urge the players to do more of team work if they can do that then the team will be ready to win the champions League competition next season.