Alonso’s departure will definitely be felt in terms of charisma and the confidence he instilled, but Ten Hag now has a chance to reshape Leverkusen into a different but still competitive team. The Bundesliga has often seen clubs rise when a coach maximizes limited resources, this doesn't mean Leverkusen should relent on new signings, If the take advantage of the transfer market and make some smart signing they will stand a better chance of competing for the title.
Alonso gave Leverkusen a chance to feel more confident then they have ever felt as a team, he also Instilled a strong winning mentality that reshaped their minds into not settling for a defeat even at times when it felt like they were already defeated, he will be missed by the team and even the players. Ten Hag has got a challenge with his relationship with players and that has affected how he relates with his players and to a great extent it may be the reason for the kind of results he gets, I am hoping he does better with Leverkusen as time goes on.