I think keeping them so long has been part of the problem - Ribery should have gone at least two years ago. Robben is still good. Certainly think their air of invincibility has deserted them even in the Bundesliga. Underperforming (Muller in particular) or wantaway stars (Lewandowski and Boateng) and injuries (Coman) really hurting them. No new signing seems capable of making an impact (the 11 that started against Ajax nine played in the 2013 final - admittedly Hummels and Lewandowski were on Dortmund's side - with only Thiago, signed by Guardiola, and Kimmich, from the youth team breaking into the side). Lack of a big-name coach, though not necessarily a bad thing, reflects on where they are. All quite funny really