Thanks to Xavi, Barcelona is getting better and perfect. Front line progress, center, and back have collaborated with each other although are not even better from the Pep era and this progress is getting faster than what they were beginning. Against Sevilla is not difficult when they still play like this, especially playing at home with supporters will definitely win with 2 different goals and shift the 2nd position.
Xavi has done great job to bring Barcelona to top level. They revive career of Dembele that is impressively if we know a few coaches failed with that mission. They have only 3 points less than Sevilla but have one more match. If they win it, they will have the same total point as Sevilla have. Barcelona can finish this season in the second position that is unbelievable at the beginning after the leave of Messi in very final day of transfer season.
Yes, I think Pep's squad is still above Xavi's players today. I remember when the era of puyol, xavi, iniesta they seemed to be better. I think the Spanish League went down a bit when the two world stars left. The quality of their game has decreased a bit. Barca have begun to rise, Pep's philosophy passed on to Xavi. Xavi gave the same touch as Pep. They do not remove their characteristics.
You are right. Current players in current squad have lower quality than the one Pep had years ago. The same for Real Madrid with their current squad now. However, the interesting fact is because both of them have decreasing quality, they are still be parts of a competitive race in La Liga.
The next season will give us a clearer overview on what Xavi and Barcelona can actually do. They will begin it with fresh mind and higher ambition. If they end this season in the second position, they will surely aim at championship next season.