I am sure that Bayern Munich will be the Bundesliga champions next season if they do not make any big mistakes or stumble.
Apart from the players that Bayern Munich have and have got in the past they should be getting every time the Champions of the German League.
For now you cant say that they will be not doing or making any mistakes , other teams are making there homeworks and getting better.
So for sure there will be next season some games where they are struggling to 100%.
Dortmund and Leverkusen can be considered as Bayern Munich's main opponents. However, we have not seen good performances from these two teams this season.
Dont know what you are have seen , but specially Dortmund showed some improvements the last weeks of the season.
And not every game that was played from Munich was good , and i guess that the next season will be more close as it was the last one.