Kinetics I've been seeing a lot of your recent signatures and you have been showing growth and potential for even more growth left and right. This signature right here even though you lacked execution the concept is that of a very high classed signature. I will try to explain to you ways of not "fixing" because it isn't broken but ways of "adjusting" certain effects.
First your concept is really awesome. This sort of style is something that I would totally do, maybe that's why I like this Tag a bit more above the others. The Orbs being covered by C4D's is also pretty cool.
Some things that I would tell you to adjust are your; Focal, Orbs, C4D placement, Gradient mapping, Vibrance levels and Photo filtering.
Focal:
Your Focal is in the middle, it's never good to have your focal in the middle. Whenever you make a signature or any piece of work it's always best to follow the "Rule of 3rd"
http://en.wikipedia.org/wiki/Rule_of_thirds. This will not only increase your focal on full-body/upper-body signatures but it will also help a lot with depth. Remember that the primary goal of using the rule of 3rd is to place your focal (part that you want people to focus on, primarily the renders upper body) where the lines cross.
Vibrance Levels:
See this piece is really bright because of the background, so if you lower the shine and the colors down a bit and turn it into a "dull" colored signature this puppy will lose it's "hard color" look and will look even better. I believe that even by just doing this step the Tag will look much better, you don't even have to do much to it.
Orbs:
Your orbs look a bit big...and though that's not all bad, it just makes it harder for you to be able to blend them in better with the background. Remember that when adding orbs the best way to make them look like "energy spots" is by covering most of their outline to remove that "3D" look. The best way of covering up most of their outline is by placing your C4D's around the edge of the entire thing or using a small hard brush yo "extend" your C4D's coverage zone.
C4D placement:
See, in this case your have some C4D's that work with the signature. The upper right hand corner C4D would work wonders for you if you would have had placed it in the upper left hand corner, it would have added an extra effect to the signature. The end result would have looked as if that was coming off his hand or/and as if he was controlling it.
Gradient Mapping:
The red from the background and the red from the renders clothing are a bit different, not by much but by enough to be able to tell with a single glimpse. If you set a Red+Black gradient map on normal, then lower it's opacity until the render looks like those orbs are emitting light to his skin/clothe then it will look blended in. Which brings us to gradient blending, even though the tag is red and black, you don't want to use just red and black to blend the colors in, you want to try using light blue and black to even out tones etc.
Last but not least Photo Filtering.
When using 2D renders it's always a good idea to use Photo Filters because the skin can take weird colors or even burn (white spots) if you adjust it too much. Although people confuse Photo filtering with Gradient mapping, they both have different effects and affect the signature in different ways. While a gradient map changes the tone of two objects, the filter will even them out. In this case if you use a soft green filter it will even out your tones by a lot because it's never good to have too much red in a tag.
Good luck, keep it up and hope to see more from you.