Hey,
I liked the sound you achieved, but if I were you I would work a little on your melody, as with the same motif it could be stronger maybe with a different order of those motifs. When it starts it feels like a beautiful tune, but throught the piece I flet like the dynamics were a bit disconnected to that (maybe the piano is too forte for the tune and not with enough contrast within itself, strings are a bit too much, etc). When the strings enter first, maybe you can try to make them a bit more supportive in piano instead of taking the lead, and keep that lead for later on in the piece.
Also a bit of a change in orchestra colors would be nice, maybe on the first entrance of the strings you could use the woodwinds to do the melody and save the strings for later, or start the melody with the celli in a different register so the violins are not just simply following the piano... You have many different possible choices.
Regarding the A and B sections, I'm afraid they didn't work together very well and you put yourself on a difficult situation, as it is very difficult that you can guide the listeners smoothly between different meters. You spent the first third of the piece in 3, and then you switch to 4 when the perc enters. That is difficult to make it work, as the vibe is too similar but with different meters.
I think it would work better if you keep the second part with the percussion in 3 instead of switching to 4s...