I just finished a paper on Lutoslawski couple days ago, and am quite satisfied with it. I also read many of his writings and interviews. There is something he said that is so interesting (irrelevant to my paper topic): L regarded two main trends of music in the 20th century, that of the Second Viennese School's and Debussy's heirs'. The Second Viennese School is generally regarded as the complete opposite to the main stream because they disregarded the function of pitches by equally distributing the chromatic scale, but L suggested that they were the one that continued the tradition by completely disregarding it. The other pole was Debussy's harmonic language, which completely revolutionized functional music and its order and construction.
I could not agree more. Schoenberg consciously avoided tonal function; Debussy just ignored it.