The only possible reason to see bayern lose bundesliga trophy this was is leverkusen. I see that if leverkusen is only worthy competitor for bayern right now. Dormund was almost making it last season but 1 mistake made dortmund being trophyless last season.
The thing that is worrying me if real madrid will take xabi to be a new appointment. It will make leverkusen backs to the its mediocre form. I can't even imagine it to happen with leverkusen caused by xabi is a very important coach for leverkusen.
Signed kane from totenham doesn't mean bayern can win bundesliga easily. Leverkusen is the only biggest wall to make it happen this season.
Leverkusen is as strong as bayern right now. The duo bayern is now in the title race for bundesliga trophy this season. The second leg for duo bayern will be very interesting caused by the game will be happening away for bayern munchen.
I think you overestimate Bayer, they are good and temporarily successful, but even this season Leipzig achieved more - they took the Super Cup from Bayern and did it as painfully as possible - with a score of 3-0. By the way, bookmakers agree with my opinion:
Fc Bayern Munich 1.20
Rb Leipzig 11.00
Bayer 04 Leverkusen 12.00
Borussia Dortmund 15.00
But in fact, all this matters little since Bayern will become champions and no one will stop them, and the odds of 1.20 look like a gift.