Last night I heard a piano graduate student play Mozart C minor Concerto, No. 24, first movement with a pretty good mostly student orchestra. It was striking in that this highly trained soloist apparently had no way of processing the passion and the darkness that meet headon in this taxing and all-too-familiar work.
It brought back memories of my own bewilderment as a high school student playing my first concerto, the Mozart A major. I will never forget the impact of hearing for the first time instruments of the orchestra play the "same" music I was playing. The color of their sounds, especially the winds, still moves me.
Yet I, too, had no way of conceiving passage work--arpeggios, scales, etc.--as anything but flashy. It had never been suggested that such passages were not simply a reason for showing off, but might be pianistic elaborations or particular tone colors. That an arpeggio might be sad, or longing, or tragic--who knew?
The irrefutable proof that the movement is not about virtuosity for its own sake is the soft ending.