Xavi departure will have a bad impact on the coming season because we never know whether a coach who has intelligence like Xavi will manage the existing players well without being able to bring in quality players like other teams.
persisting to stay with Barcelona is also one of the bad things for the achievements that the coach will get because being with Barcelona for too long will certainly not give you more experience.
I can't imagine what Barcelona will be like in the coming season without Xavi and it will definitely look very bad and the fans will definitely be very worried.
This is what Barcelona management should be wary of next season after Xavi decided to quit at the end of this season, if Barcelona is in strong finances like a few seasons ago, of course the decision to step down the coach is not a problem for them because they can easily find other coach, but next season of course will be different, currently Barcelona is in a bad financial condition and it is difficult for other coaches to take responsibility to bring The change in Barcelona who does have a limited funds to compete in La Liga and the Champions League, Xavi who has a love for Barcelona is able to bring Barcelona on the right track even though he does not have strong financial support, but I think it will be very difficult for other coaches to be able to do what Xavi is doing at Barcelona at the moment.
Barcelona have indeed got a replacement for Xavi next season, but honestly I am not sure if he is able to lift Barcelona's game performance next season, currently Rafael Marquez who is the coach of Barcelona B is reportedly a strong candidate as a replacement for Xavi, although maybe he already knows Barcelona well but of course the pressure to be able to face big games will of course still exist.