more sub bass.
i think a punchy kick will do you good.
if it came to a live setting, i dont know if i could groove to hard to that, focus on building that groove.
when it comes to producing dubstep, what i do is completly focus on my drums to start with, make them have that "dubstep" feel to them then once i am satisfied, i work on the "wobble" and add whatever other things to it to get that deeper, larger sound.
P.S. a small amount of reverb on the dubstep synth will make it sound alot bigger, what program are you using?