It looks like Dortmund will need to make substantial changes in their squad to be able to compete with Bayern Munich for the title. Because the same things happen every year. Dortmund go on by a decent performance for some time. But at some point, they start losing their discipline and getting unbelievable losses. And this causes the interval between them and Bayern Munich to increase a lot. If Dortmund make the necessary changes in the team, they can reach Bayern Munich's level.