I'm noobish in the ways of the draw so take my words with a grain of salt. While it is that the factors that you've listed won't break yer pic, my hunch is telling me what betrays your sense of being finished is... that your subject isn't fully drawn!
The subject is all we, the viewers, see in this picture. We have no background, no supporting characters, only the subject and three props. We need more info to further define as to why the subject is posing as such and his relation to his light sources. I suggest adding in the rest of the character! Complete his body and give in a soap box or sexy servant! Edit the more obvious shading/highlights to eliminate the confliction of where the light source is emanating from (Unless he's close to something which is reflecting the light?)
I wish I could help you further when it comes to light sources and suggestions, but I'm still noobish in the world of drawing. If anything, I'd highly suggest just taking notes of the flaws that you're aware of and just move onto the next image.
TLDR Version:
Finish up the rest of the subject (Legs, hand, tail, soapbox) and edit only the obvious highlights which conflict where the light is emanating from. Define as much as you can for the viewer, it'll help translate the image better. Don't toil on this image too long, move onto the next pic!