I think Edward Elgar's music is difficult to pull off, oddly similar to Bartok in a way. The pieces that have traditionally gone over well in North America are pieces that speak for themselves. You can hear a horrible high school orchestra play Beethoven's Seventh, and you will still know it is great music. The Elgar Violin Concerto is great music that demands a great performance, and it requires a very special skill set from the soloist.
