The Bundesliga title still looks quite easy for Bayern Munich to defend, even though currently Bayer Leverkusen and Sttugart are still quite consistently in first and second place. It's only been six matches and we often see that several clubs have difficulty maintaining their best playing performance, apart from the reasons why several players have suffered injuries and there are other factors that might make it difficult for them to appear consistently. Bayern Munich is still on track to win the Bundesliga title and I believe they are still one of the strong candidates this season.
Everything will depend on how consistently Bayer and Dortmund can play throughout the season. Bayern have problems with defense (in particular with the goalkeeper), but they can offset this with good attacking play, and they also have a strong bench. Dortmund traditionally experiences slumps after the middle of the season, in most cases due to player injuries, and we will soon see what Bayer is capable of.
The sad thing is that we all know those teams will not play all that easily and better most of the time. The "consistency" part is the hardest part for these teams, if that wasn't the case then Dortmund would have won it already, just last year is still on their minds and should be something they will have hard time fixing as well.
I think it should be very important to remember that you are going to end up with something that will hurt you on the long run. I know that it will not be all that simple but you could potentially have it one way or another. This means that you are going to end up with a result that will hurt you and you should try to avoid it as much as possible. I know that they are doing fine for the time being, but that doesn't mean that they are going to keep doing fine forever. They should try to be as consistent with their wins as possible.