Uhmmmm...
First of all the idea was really flabbergasting!
The concept was alright and really justified...
But...
Technically speaking, mastering is a bit off. Let's take it in different dimensions.
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When you are doing songs with vocals, always remember that you must emphasise the vocals, only supplemented by other instruments (i.e. synths, etc.) with only exception for the drops. So you have to add oomph on your voice. And as a singer/performer, you must clarify and power up your belting skills for such songs like dubstep fused with vocals

Instrumental-wise, stereo imaging is a bad idea for production if you cannot handle it properly. The sounds (especially the mid frequencies) are relying as panoramic. So my point is, reduce the stereo widening.

Mixing-wise, add space in your drops, especially the basses. Reduce the melodic synths, or, just put it when the kick enters then alter the bass when snares comes in. Also add clarity to the kicks and snares. In order to do that, EQ it! For kicks, add more mids and bass or put the peak in low mid. For snares, add some lows or also put it in low mid. And also add some sub bass and sidechain it with the signal to the kick. It may result to simple but powerful sub bass design.

That's all!
Enthusiastically,
-Uxvellda