no focal, flow, text is impossible to read on the left side, and the lighting isnt good. your depth is well done. i would give you ways to improve but.. im busy
the image seems cut of after the arms, I assume his lower body would show a little bit... I don't like the focal point either, and make the text stand out more.
Well, generally when you use a radial effect or texture, as you have here, it is centered behind the focal, it really should not be centered on the canvas. You blurred your name when you were adding depth, and when you use vector-style graphics, it is best not to blur them (referring to the radial effect). As KnightKninja said, the lighting is off because a) the spartan is over-exposed and b) because there is no light source or lighting at all on the background of the sig. I would suggest using the Burn tool and Levels Adjustment layers to tone down the lighting on the spartan. Add a light source, and move the radial design so that it is behind the spartan. Use a gradient map or two to tie the colors together in the sig, and change the font and placement of your text. Those are just some small changes that would significantly improve the sig.