Hey Michel!
First of all, can I ask: This is a GPO rendering? Cause for GPO it is amazing! Don't let Gary know I said that, but I always consider that there are better libraries than GPO, yet I'm proven wrong, but people like you.
I have already heard Part I, and listening to part II.
Will post as I'm listening.
Note that I don't have time, right now, to look at the score (and nobody should ask where I got it

), but promise to do so... Might find an error as well, who knows... hehe
On Part I:
It has some great moments, but while I was listening, I was having the same feeling constantly for 7-8 minutes. I was missing some major direction. Form wise.
You should know that I'm deadly obsessed with form, so I need, deeply down a strong sense of direction to lead me somewhere. And it is something I lack to major composers, and I can't stop telling them off!!!! although of course it's not my place, and of course it's a different take and path to what I take, still.. :-/ I can't help than feel this way. Thus my comment above.
The harmony as well, didn't seem to be leading somewhere... But I have to say that I enjoyed the preludium much more than the scherzo.
On part II now. This IS beautifull. Could be that Matt is missing the whole image (although I do understand what he means exactly... And since it is divided in parts, he can listen to 1 part and post about it...). The usual problem with sonatas I guess.
Here the harmony works great for me, and the melodies are also much better "defined". The tiny gaps (I think I noticed 2, but could be 1), are a major breathing point (I'm talking about the part were the nocturne leaves us for the march to enter!)
Great march feeling as well. All chords work miracles here, and the strong tendencies of the melodies in the clarinet are... something else.
Part III now:
A great feeling for the Arioso. More tonal, maybe in a way, but certainly lovely and QCCian! hehe!
The rondo, I will admit that felt a little bit borning. :-( I'm sorry! It just felt like redone food or something, if you get what I mean. I felt like a dacapo (not entirely of course) and I'm not sure it was needed. Of course, the idea of the rondo is to exactly bring back memories of the first movement...
Great finale though! (after the rest)
I will admit that this is a kind of music that I, personally, enjoy listening. It's not an ugly Avante Garde attempt. It's not some contemporary composer, who studied music for 3 years, and started writing contempary music, and when you ask them they can't shape a single normal melody. It's Music, with a capital M! It is something that I would gladly see in a concert. It's not, one of these things (that I so much love writing

) that have some kind of meaning (real, or pretence, in my case, doesn't matter), or a deap bottomless feeling or so. It is a sonata!
Phew...
That's a lot!