I'm no professional or anything, but I'm super picky - and this music you've created here is one of my favorite genres (I call it "Epic" lol)
Personally, I'd like for some more 'color' in both parts in the first theme. You might be limited to the ammounts of tracks you can use, but AT LEAST in the staccato part with the clarinets, can we get anothe rvoice in there (preferably a mid-voice - viola, high cello, F Horn, something) to round out that sound? And if thats already present, maybe increase it's volume.
Throughout I'd also like to hear some dynamics. I don't know if you're limited by this either - but the volume level is pretty stagnant throughout. We don't need any big drops of volume, just some more noticeable crecendos in moving parts, countermelodies and such and especially in the brass melody. Follow the contour of the line, if pitch rises, increase volume a little.
Please let me know if this all makes sense / is do-able / sounds reasonable to you? :)