That is an interesting post Tanuj - I agree about the Korngold F# Symphony. Have you heard his so-called "Sinfonietta" ? (If that is a "little symphony" I shudder at the thought of what he thought a big one was - maybe something like Gurrelieder?) Actually his first symphony, which was written when he was 14. That fact alone makes him a prodigy the equal of, or superior to, Mozart. Because of the extreme harmonic and contrapuntal complexity with utter mastery of form, development and orchestration. But it also has an Adagio that is as beautiful as Bruckner's adagios. And of course his opera Die Tote Stadt which is one of the few modern operas that can compete with the great classics of Verdi and shows Korngold's wonderful late Romantic morbid streak. It also has an incredible orchestration that film composers would love to emulate. It is interesting how Korngold viewed his film scores as "operas without words."
Actually Korngold shows the same thing you are saying about character - how could "training" account for his writing that symphony when he was 14? Music is just there, in your brain. The training may help you get it out, but it has to be there to begin with.