Now since the season is over, the teams are trying to improve the team and hire more and better players for their teams to have better performance in the next season. But, I think considering the performance of Xabi Alonso and his players during this season, the main goal for Leverkusen should be keeping the players they have and they should try to have a more stable team.
If they can have the same performance in the next season, they can be definitely the main team to race for the Bundesliga title and they can even have hope for the Champions League.
Bayer has a good squad, maybe Alonso will try to improve some positions, but he shouldn’t demand big finances for transfers. The next season will be a new test for Alonso, whether he can repeat the success in the Bundesliga, how Bayer will play in the Champions League, these are all very important questions. If Alonso had left for Bayern and Bayer's results had worsened, everyone would have said that the reason was obvious, but if he decided to stay, then he would have to work even harder, staying at the top is always more difficult.