dazart, I disagree slightly...the average trained classical pianist, would have a heck of a time trying to master the arranger..Why, most seem not to be trained well in theory, and are uncomfortable playing chords or understanding the chord progressions..They usually are trained to be strong site readers and playing technics..Many do not portray the emotion that none classical students can show...

Maybe in piano mode they can get by, and I mean that literally...
Keep in mind, I am referring to the average classical trained pianist..

Your other points are valid, although, there are some of us that can play both...