Bayern Munich are the natural champion and strongest favorite of the German Bundesliga. Whether they sign Harry Kane or not, they will be the strongest champion candidates next year, but they managed to become champions due to Borussia Dortmund's fault in the last match last season. Also, they haven't been able to make a good striker transfer since Lewandowski transferred to Barcelona. I think they need Harry Kane, or at least as good a forward as Harry Kane. For this reason, they want this transfer so much and they are making an effort in this direction. I hope they will be a little more willing and spend the next season more comfortably.
In the recent form of Bayern Munich their vulnerability was shown and was spotted by Dortmund for sure if you look at the previous season of the Bundesliga well it is because of the lack of a striker and that wasn't filled in by Sadio Mane actually their dominance status fell apart when Robert Lewandowski decided to be transfer into Barcelona, for sure this is the move that Bayern Munich will regret, but Lewandowski is showing interest in getting transferred,
While i agree that Diaby was a very talented player that made the difference in a lot of matches for Bayer Leverkusen, i also think that he had quite a few matches where he showed pretty average or bad performances so he is still lacking the consistency in order to become a real world class player. Therefore i think this was a very good deal for Bayer Leverkusen even though his qualities will definitely be missed. They will get 55 Million € for him (+5 Million of possible bonus payments) and for that amount of money i am sure they can definitely find a proper replacement for Diaby i am pretty sure they already know how to replace him.
We can not blame a player for having a bad day well they are not perfect after all and surely some needs comfort, if people are seeing their strengths they should also see their weakness I really think if they can show their weakness to their team that will be a very good thing because they can surely deal it as a team, and not as an individual,
Well Diaby is a precious player for Leverkusen and just like Bayern Munich to Lewandowski it ius surely hard to replace what the others are used to, but it is very brave if they would let them know that you certainly have a weakness, that your team might have a solution on it,