I'd agree with Jazzy Kendall about the ornamentation. However, my personal taste is for almost no ornamentation so listening to me on that point probably wouldn't help you. You seem to be interested in exploring your exploding ornaments. Run with it.
I'm typing this as I listen and follow along in the score, come along if you'd like....
The trumpet's register shift at m. 14 was a really nice touch. It made the piano's new role as imitator that much more special. Really good call there.
The piano part looks totally fine for any competent university level pianist. There was ONE figure I took issue with though. The arpeggiated piano figure at m. 21. Those repeated notes complicate things enormously. That's not to say a competent pianist couldn't do it but you could get almost the exact same effect with something much easier to play. The pianist will know this and will probably curse your name as they practice it. Either that or they won't practice it and will fuck it up at the performance. Your call.
As for the piano part as a whole... the stretches don't seem to bad. I would definitely consider a rewrite of those arpeggios with the repeated notes on top and bottom. I've got a keyboard in front of me and I figured out a fingering that works but why tempt fate? A quick fix would be to just leave the first 32nd note out of each octuplet as that space is already being played by the other hand. That way you still get that nice effect of the repeated top note which seems(To my ears anyway) to be the important part of the figure. It would make it MUCH more intuitive and your pianist will thank you.
I didn't really dig the deceptive resolution of your V7 to flatVI at measure 30. I think what didn't sell for me was the sudden forte in the piano part. If you put a crescendo through that bar(Like in the trumpet) it would probably be a better sell. Another solution would be to use a really special chord there that you hadn't used before and extend the V7 through to the Bminor chord in the next bar. A newer, specialer, bolder chord there would really drive home that moment as THE "IT" MOMENT, which is what I assume you're going for there. Your call though.
Definitely reminded me of Rach's Vocalise. You shouldn't have said anything
.
Is that opening chord progression taken right out of the Vocalise? I swear I could hear Rachmaninoff's cello line over top......