I am getting goosebumps as I listen to this. And I agree with Unborn-reason that the choirs add a lot to this. Your orchestral skills are obviously apparent though, and are the shining point of this piece.
If I were to suggest one thing, I'd say add a couple more bridges in the song that vary the energy levels in this song. For the most part, it feels like there is one energy level pushed on throughout the song. If you know what I mean, adding a couple more areas in the song that lack energy will make listeners appreciate the energy of the chorus/main parts even more.
And also maybe add a couple of bridges that are even louder/explosive with bigger and more instruments playing with percussion pounding and crashing.
It's hard to critique since it was already well done, but I just like to give some advice to everyone.