The mix was accepted over 5 years ago. Quality standards change. At the time, the sounds used there were probably close to top of the line. Music production has evolved at such a rate to make some of the best sounding old things childish in comparison to more modern offerings. Look at how far gaming consoles have evolved over the same period of time.
Firstly, everything is mastered fairly quietly. I understand that you want to have dynamic contrast, but in this case, it's to the point where I can barely hear it until 1:50.
The brass in your mix sticks out fairly sorely. There's quite a bit of unwanted squeaking coming from those high note stabs in...some instrument I can't readily identify. Maybe a flute? It doesn't really vary, as you yourself have said. Throw in some of your own stuff. Add a little interlude to break away from that main theme. Get creative. It will help you immensely.