here is my crit. Basicly Make the diffuse darker all over. Then make a copy of the diffuse with out the GI overlay and invert it for the base of the spec map. Up the contrast and add the GI over that and add some grunge to break up the spec.
Yeah actually now that I think about it, in the places where the diffuse goes very black, have you tried giving it a rough bumpy texture, and increasing the specular more than surrounding areas? I think that'd look pretty cool.
update i tried to add more subtle colors besides blue like some cooler colors in the shadows and some yellows on the highlighted parts. I also propagated the height info from the diffuse into the normal map. Oooo a turnaround! http://www.mvelasquez.com/images/insectguy/insect_turnaround.mov