I think that you gave too much to the visual part.
The brass and cymbal are super repetitive,
don't worry, changing them a bit won't make it less epic.
Don't let others define "epic" for you,
the fact that many just use four repetitive chords doesn't mean you have to do so as well.
I mean, you can keep them if you want, but at least please change... something
I guess that in order to create what's defined by today's society as epic you have to use a four chords loop.
Then at least please change the bass note.
As you probably know already, Dm can not only have a D as it's root, but also F or A or E if you wanna go wild.
Also, you four chords loop doesn't have to include the exact same chords every time.
Try making an eight chord loop with a tonic in the middle so it keeps the four chords tense and relief circle.
Other than that, I think that your choice of instruments was good.
*p.s. now I listened again and heard that you changed the base line somewhere around the middle.
I still think it should be less static. Moreover, I think you should change scales and add some crazy runs and choir or something.