Dortmund and Leverkusen won't pose a serious threat to Bayern Munich this season, as neither team is yet on par with Bayern Munich in terms of strength. However, if we look at the details, Dortmund might be better than Leverkusen this season, although Dortmund won't be able to break Bayern Munich's dominance this season, as Munich remains quite solid with the depth of their squad. I wouldn't expect anything less from Leverkusen or Dortmund this season, as Munich will never neglect any opportunity to win this season.
This si aa point of view I will support, Bayern Munich is currently on a very different level as compared to others. Leverkusen who we were hoping to be the threat Munich will face has turned out to be a weak team now with their performance meanwhile Dortmund is still looking very much average in their performance so far and they do have this style of no pressure and doing only as much as they can do at a time. I will even suggest you drop your expectations on Leverkusen because they may disappoint due to the performance they are putting up now.