Does success live and die in one season? He has done for Dortmund, with far less finances, more than many far richer clubs in Europe. He has made several strong players into bonafide stars. Players were that then sold out from under him. Reus is soon to follow. Lewandowski was sold and his replacement was Immobile. And that was supposed to give him the offensive power he needed to compete.
He has formed younger players into very good ones but Reus is not one of them.
He came to Dortmund for over 17 mil euros and was already the player of the year in the Bundesliga.
The guy who really formed Reus(and played him at his best position, which is not the wings) is Lucien Favre.
The thing with Dortmund is that they, like nearly every other club besides Bayern in Germany, get important players taken away and have to replace them.
If you want to still be successfull, your transfers need to be pretty good and that's something they haven't been able to do for some time now.
Also, the league has learned from their matchups with Dortmund and just doesn't play to their strength anymore. So instead of going forward, they're just giving the ball to Dortmund and sit back, which makes Klopps tactics useless and it seems like they don't have a plan B.
On top of it, guys like Hummels, Subotic, Mikki, Gündogan or Pisczeck haven't been good at all while important guys like Reus or Sokratis have missed way too many games.
Though, the worst thing currently's that there are still people looking at the table and talk about how many points they're behind a CL spot and nearly everyone talking about them being too good to not get out of the relegation zone quickly.
All that while the team can't win two in a row and always loses against teams like Bremen, who're really bad.
For them to get out there they should concentrate on winning some games and reaching that 40 point plateu(pretty much secures you to stay up). If they do so and there are still some games left, they can try to get more out of it...