Staying with Xabi Alonso increases Bayer Leverkusen's chances of retaining their title, especially if Xabi can get the same atmosphere as he got last season, getting the club's full trust to build a strong team because management intervention is often excessive which will create an atmosphere at the club it gets bad.
In my opinion, Xabi's task next season will be much tougher than last season's because there are two titles to defend and they will be playing in the Champions League, when there are bad results, sharp criticism will be directly addressed to him and that will increase the pressure on him as well as the Bayer players, no many clubs in the Bundesliga could win back-to-back titles if Bayer can do that which is very impressive, but I don't think they will return to their unbeaten record because that is something that is much more difficult for them to match.
The fact that Alonso decided to stay at Bayera of course ultimately had a big impact on the mood in the team and made future goals clearer. It is clear that the team does not want to sell the players with whom they became champions, this is noticeable by the prices they set for the transfer of players. Of course, Alonso will try to repeat Bayer's success in the Bundesliga again, but I think that this time it will be more difficult for them to do it. I also want to believe that Kompany will be able to improve Bayern’s game, because it is not yet clear how well he can do his job.