Leverkusen had one good year last season, and that's it, nothing more, which is why I am not expecting the whole world from them, doesn't make sense. I believe the best thing right now for them would be figuring out what they could do for the long term because Xabi will leave, Wirtz will eventually leave too, so they need to figure out what they can do after they are gone, not just focus on this season.
A Bayer Leverkusen team that can't defend the title this season is not a burden for the players and the coach because their success last season lifting the trophy was the first in history and will always be remembered by everyone from the fans to the management.
I also don't expect much from them, in fact I recognize them as a solid team when they already have a chance to win the title at the end of the season. That's what distinguishes Leverkusen from other Bundesliga teams when they have a big chance to win the Bundesliga. Which team I mean I don't need to mention.
Players leave because they are targeted by other clubs, that's a good achievement. For example if Alonso goes and Wirtz goes then they deserve to have proven themselves.