Xavi is a good coach for Barcelona in this time. They have found a young and talented coach who was home-grown in La Massia and is supported by fans of the club.
Xavi in management aspect has shown that he can do it very good. He brings some fresh air to their players, improve their mentality, belief and revive career of some players there, from Alba to Dembele. He convinced the club to bring Dani Alves, Traore and Aubameyang to Nou Camp. They all have contributed good things for Barcelona.
They must bind their future with Xavi if they don't want to bet with another coach and fall into crisis again. In fact they failed with Koeman before Xavi came and fixed it.
I agree with your opinion on Xavi's success at Barcelona this season. He may have failed to bring a single title to his team this season, but he has not failed to improve on Barcelona's previous poor form. He has fired up his players to achieve good form in a game, and the real testament to Xavi's hard work this season is that Barcelona are likely to finish second in Laliga.
Regarding improving the performance of several players such as Dembele, Aubameyang, Ferran Torres, Pedri, Alves and several other young players, I think it is the result of Xavi's hard work for Barcelona. He has managed to convince his players and he has brought the dressing room atmosphere to life. Yes, I fully respect Xavi's success this season. I'm disappointed that they didn't win the title, but I'm happy with the improvement in his team's performance since he took over as coach from Koeman.