I actually think them losing Xabi Alonso as coach and some players is going to cost them Silverware in the coming season. Bayer Leverkusen will be like the Old Borussia Dortmund that would most of the time play second fiddle to Bayern Munich.
Building a team that coordinates so well like Bayer Leverkusen did last season takes a lot of time.
I won't deny how impactful Xabi for Leverkusen, but life must go on. They must not be always overshadowed by him, and have to believe in Ten Hag as their new coach. I dont think Leverkusen will be downgrading so hard under Ten Hag.
Leverkusen has so many ready play players as Xabi's legacy. Adding Ten Hag combined with Goatony is enough to help them in competing with Bayern Munich.