Xabi Alonso made an excellent decision to continue with the team next season. Leverkusen will play in the next Champions League, they will need a coach like Xabi Alonso because he has played in major competitions such as the Champions League. I can't wait to see the club compete with the clubs from other leagues, as we have seen how they competed with Bayern Munich for the Bundesliga title race this season. You're right, they need to add more players next season, so they shouldn't be eliminated so easily, because they will face difficult challenges in the next Champions League if they meet a major team like Real Madrid or Manchester City, we don't know if their current players will have strength to play this way next season.
This is an unexpected decision, he had so many opportunities to move to another more top club, but he decided to stay at Bayer. I don’t know what to say, in my opinion this is not the best decision he could make, perhaps he is counting on the fact that next season he will be able to repeat all the success again. I think that he will not be able to repeat the same thing next season, perhaps this is a mistake, especially if the next season can be worse, he will not have as many offers as now. But this is his choice, apparently he just doesn’t want to change anything.
I think Xabi has made the right decision even though most people really regret what happened where Xabi rejected the offer to become coach of Bayern Munich and Liverpool, but looking at the quality and stability of Leverkusen current performance there is still big chance that next season will perform well.
Unless there are some problems that occur that might affect Leverkusen performance and make their condition worse, I just not sure that Leverkusen will experience serious problems as long as they all work well.
In addition, Leverkusen will participate in the UCL competition next season and that is good opportunity for Xabi to show his performance as great coach by keeping Leverkusen competitive even though they have bigger and stronger opponents.
Moreover, even though for now Xabi has rejected the offer, there is still possibility that next season Bayern Munich will make the same offer again.
And the priority for these two teams now is that Bayern Munich is focused on the UCL competition which has reached the quarter-finals and Xabi is focused on bringing Leverkusen to the semifinals of the Europa League so they can continue fighting to win the title.