I respect that, but by multiple light sources do you mean the two? The point is that there is a glow coming off of his sword, and the other light source is the primary one. I agree the C4D effects do look spotty, in my defense it happened once more contrast was added after uploading it. I can't find a site that doesn't effect my quality, even dA did more than the one it's uploaded to now. ):
I'm sorry if I'm coming off as defensive, I just don't agree with some of your criticism but I did consider it before just jumping to argue.
And as for the emptiness, I think that depends on personal opinion.. negative space is VERY important in all works of art. I don't believe in overcrowding a signature or anything, for that matter.
Again, sorry for the tl;dr.
Edit:
I decided to soften the image, and make the lighting a little less spotty.
What do you think?