There is a difference between this Barcelona and Koeman's Barcelona, there is so much difference between the two. Xavi has really improved this squad with many talented players this time. In the time of Koeman, Barcelona looked like an average league team, nobody feared them last season but Xavi has been able to transform the team to some sort of standard to compete with Real Madrid in the league.
You are absolutely right, that was one of Xavi Hernandez's successes for his first season at Barcelona. In the second season Xavi increasingly dared to make many changes, especially regarding the composition of players he must have. A number of new players are bought and signed both for free and at a hefty price tag. Barcelona's management sacrificed a lot this season to make the team better, and now Xavi Hernandez has to prove his capacity for titles.
This season Barcelona is expected to be better after their current squad is very strong in various positions. But there are no guarantees about their ability and consistency about winning, so the title shouldn't be easy as long as Real Madrid are still in the lead.
Barcelona was very weak during the time of Koeman and when xavi took over as coach it was never a problem for him to transform the team, he transformed the team within a very short time to think about. Xavi was able to help Barcelona to get to a better position last season. I think xavi is still building Barcelona, that is why Barcelona is getting more better. The hight and strength that Barcelona has now it can lead them to win the league this season. Real Madrid will find it difficult to try to win the league.