Borussia Dortmund use to be very consistent on there Bundesliga then but now a lot of things has changed about them, though Borussia Dortmund is well known in terms of generating a good players because the above listed names are currently doing very well on there current clubs.
Borrusia Dortmund have to spark their shining stars because that's the only path to bring them back to winning ways. It's never going to be easy for them because the board made huge mistakes in previous seasons. It's never been an easy road for Borrusia Dortmund, they sold all the potential talents and left with nothing currently. However we have nothing to worry about because they're always lucky to have in possession incredible young players.
I don't think the board of borrusia Dortmund did made a mistake, it's been in their policy the trade of players be it their star or not, they make good profit of it and at same time are able to breed new set of players that still helps them stay a float such that they always maintain decent stance in the table most often than others does. What I see is happening at this time is the change in the era and breed of players such that what was applicable before may be fading away except if some adjustments are made to get it suiting into the new era least they get the team setting back with their performance and results.