The attack of the french? horn sound in the beginning sounds kind of abrupt, like it cuts off with each new note.
Does the tempo increase during the piece? I liked that, even if I'm hearing things.
The mixing sounds a bit cluttered when more and more instruments come in; it might benefit from deciding that some instruments should stand back and others take the front, and even alternate this during the song. For instance, the strings could be further back in the mix in my opinion (after the intro), and the piano could also be mixed lower when there are other leads going on. You can mix say the piano lower in certain parts and bring it up in others.
It cuts out at 3:16 right?
Overall an enjoyable arrangement, I liked the instrumentation and the way it was growing.