I have to admit I couldn’t see the speckling you were referring to, so I can’t help you there. But I can give you some general feedback.
I love your character. The pose is dynamic and doesn’t look stiff, like so many do at first glance, and the facial expression is subtle while doing the job. Also, the way the hair is blowing back just a bit gives action and implies something powerful is going on.
I like the lightning effect, and the yellow lighting on the hair which makes it seem very “there.” One small thing to consider with the lightning is moving the central nexus point up a bit. Right now it looks like the lightning is coming from the wrist instead of his palm. Unless that’s the look you’re going for, of course.
Something else is that the necklace isn’t laying flat against his chest, so the shadow underneath it can be seen. This gives the impression of movement in the opposite direction of the movement implied by the hair, so that’s something to think about.
And I really like the textures on the clothes that you’ve added. I’m very impressed. The high realism of the clothes contrasts with the flatter textures of the room, which made me wonder if this character is posed against a backdrop instead of in a 3D environment.. Perhaps tweaking the amount of bump and displacement textures on the room will bring that into balance. Or perhaps choosing a different section of the room (such as having a column in the foreground) would help. I like the position of the character in relation to the camera though.
These are just some ideas from someone fairly new to this, so take them with a grain of salt. I’m sure others will have great ideas, as well.
(On a side note, have you heard of the Fabricator, which allows you to change the textures on clothes in DS4.5 easily? I love it, and the rest of its add on packs. I don’t know how hard it was to change the textures in gimp, but you may find the Fabricator easier in some circumstances. )