There's nothing wrong with Schottenheimer. He calls the plays that work during practice, and has demonstrated that he knows how to utilize his players. Nobody here or in the media knows how the players are progressing, how they're grasping concepts, or if they're in a slump or if they're executing all of their responsibilities. Once the play is called, it's entirely out of his hands. The QB can get pressured and the play falls apart. The QB can miss an open high read and hit the dump-off for no gain. Blocking can fall apart and a 60 yard run can get blown up in the backfield. A defense can disguise the blitz and blow a play up that could have been a TD based on the base coverage.
Fisher once said, "We don't call plays that don't work." And it's true. They don't.
Execution fails and the coordinator is the goat. That's the way it's always been, and that's the way it'll always be.