I have been listening and kind of analysing some of J.W. known scores and it strikes me that they are all kind of amatourish. Harmonic progressions are often very simple (even when he obviously tries to be "modern") and when J.W. tries to flex his counterpoint muscle it seems to give away. His music has often these features:
* fast scale runs (and often plain runs, so it's not as interesting as it could be)
* slow motion in the middle voices, meaning that the chord is just held in the strings until next chord appears. Kind of boring!
* parallels 5th often used, and then not as an orchestration tool but more as a voice-leading. Now, parallels are ok but I find too much use of them (specially when not used as a orchestration tool) rather distracting. And often it sounded quite clumbsy.
* Snare drums often has the same cliché rhythm in many pieces.
* Bass is often static and relative uninteresting.
Overall, his music sometimes appears as being rushed out and rather clumbsy than a something which could be called masterpiece. Compared to the classical masters J.W. would get 2 out of 10 in composition but little more in orchestration - maybe 3 in orchestration.
I was kind of disappointed because I thought that J.W. where better than I discovered today.