One thing I really want to see is that it is not easy for Dortmund to let go of its key players, because if Dortmund dares to make the choice to keep their key players by increasing their salaries then of course Dortmund will be able to win a trophy. Because even though Dortmund always sell their key players, but the reality is that Dortmund can still compete well in the Bundesliga title race. Therefore, if only one season Dortmund can retain all its key players, then of course Dortmund will be able to stop Bayern Munich's successive title success.
11 years without a title I would call a big failure than a good competition
In general, Dortmund has actually turned into a trophy-free club - they sometimes win the German Cup, but all their significant successes like the Bundesliga title or some kind of Euro Cup are in the past. Sad situation for a top 2 club in Germany. In every other country, the top 2 (and even the top 3) have done significantly better in the last 10 years.