Because you provided a NWC score, I feel compelled to listen to it. I also didn't know anyone else who used NWC until I came here!
So, my comments from listening and looking (mainly at the piano part):
Nice start. When it speeds up maybe place the accents on the beats/half-beats to give a better feel for the new tempo. Mainly I guess this is a problem with the MIDI nature of it.
The clarinet sounds loud at (bar) 28, it sticks our over the orchestra. Is this meant to be so?
At around 35 I see what the structure of it is, and how it should work, but I feel as if there is an extra half bar in there, I'm not quite sure how to change this to make it better.
Another issue I had was with the two 'transition' bars from orchestra to piano (40, 41) I would personally have the piano taking over straight away at 40.
At 51 with eh change in harmony (at last) I think you should add in some more harmonic notes in the orchestra. As it is there is a D augmented sort of chord, with the F# only being played by the viola. I think you should change this chord to a more clearly stated Bb chord or something, it just seems weak at the moment.
At first I was confused by the apparent key change to A at around 63, maybe work on this. Having said that, it does consolidate there nicely.
I expected the LH to change at 91, it feels as if it should.
Nice start to 98.
Overall impression? A bit static in its harmonies, but that is the style of piece. I also want to hear it when it's finished.
About NWC - it is a bit annoying sometimes, but it's still way better then Sibelius in my opinion! If you get the extra font for it "NWC extra ornaments" then it is even better.
George