Might be his tendency of playing German with turkish roots out of position. Still remember the disaster of him playing the deep lying midfielder Sahin in the offensive midfield or even on the wing.
On the bright side of things, as much as this defeat vs. Stoke might hurt right now, it could be the final nail in the coffin for Rodgers, which in turn could set things in motion that could help Liverpool in the long run. Jürgen Klopp had a soft spot for Liverpool for years and if he does not want to take a break after this season, Pool might be his most likeliest destination.