Reverbs and High Pass Filters
You should look into throwing a few more effects on the instruments periodically, I like the overall structure, but you can get a lot more out of an instrument just for a small section by throwing on a high pass filter or some wild reverb on it then taking it away.
If you don't already use it, Reason is sick for this kind of stuff, should check it out. Otherwise, more is usually better, and keep up the good stuff!