He is a good GK and he would be a nice bet if Schalke gave him the opportunity to be the starter for upcoming seasons. I think DEF could be raised some points. I recall he only had one bad gameagainst Bayern where he looked way too nervous but outside that poor game, the also showed good prowess, saving a lot of shots under the goal.
I think he has the potential to become another great german GK with proper minutes.
Better to die quick, fighting on your feet, than to live forever, begging on your knees!