I'm sure they wouldn't mind becoming Bundesliga champions, but it's not that easy when the squad undergoes quite serious changes every off-season. Let's see how it works for Bayer, Alonso did everything possible to keep the previous squad, he refused more tempting offers for the sake of the team, I want to see how right he was in his decision, and how much it will help Bayer in their quest to defend the championship title. It will be difficult for Stuttgart to repeat the same season, by the way, they sold Guirassy to Dortmund, so Dortmund did two things in one move, strengthened their attack, and weakened Stuttgart's attack.
Bayern Leverkusen are still strong like last season; they did not make any changes, which I think is a good decision. Alonso knows that the squad can still do more, and since they are not facing any difficulties, I think it's still what you said earlier: we should wait for them and see how they will start the season. However, after seeing this, it makes me feel that Dortmund is smart compared to Stuttgart because they sell one of their key players. (Guirrassy)
They may be the only ones who know why they did that, but to me, that is not the right decision that they are supposed to make me feel because it weakens their position in the attack. I'm thinking Dortmund will be another tough team in the Bundesliga next season because they are also preparing it like other clubs are doing.