hey seforin! great to see how much you've already got posted, and you've done a good job in thinking out how your character would work in battle and what his technology means. i think the idea of the techmage is strong and could earn you a pretty slick looking entry at the end of all this, provided you put the work in.
my main concern at this point is that while the idea is strong, the execution at this point is a little too obvious, too basic.
what i mean is that it's clear from looking at your sketch--which is a pretty good one, by the way, nice job in illustrating how the weapon canisters work--that you've more or less gone with your first inclination, or your prevailing idea of how certain things are "supposed" to look. i made some very similar points in dejawolf's thread, if you care to read,
about the same thing. dejawolf is doing an angel of death style character, which is awesome, but the way he's representing the character in his first concept uses all the same token artifacts you'd expect from the character. the skull looks like a skull, the big angel wings look exactly like the standard image of angel wings, the scythe is a scythe, etc.
in a very similar way, you're doing the same thing on your concept, albeit with slightly less standard (but all the more stock) imagery: glowing eyes, wires coming out of his head in the way you'd expect, glow-y canisters coming out of the arms like we always seem to see, for some reason, glow in the center of the chest. you see what i mean?
there's very little that's surprising. while it's still a good idea and you're presenting it fairly well, there's not a whole lot to interest the viewer because there isn't a whole lot they haven't seen before, especially if they play a lot of science fiction games or watch sf movies.
you can still do a tech mage, with wires, glowing bits, nanobytes and the whole nine yards, but you need to consider novel ways of representing these elements, and arranging them in an interesting fashion. glowing canisters are the expected route--how else might you incorporate that sort of thing? might you find a more interesting and novel way to fuse them into his body, same with the wires? does it really even make sense to have them glowing at all?
don't get me wrong, there's a damn good reason that even the best artists end up using glow-y bits in their designs...because it's an easy, great way of making something look cool. but if you do the glow-y bits in all the familiar ways, then the viewer's brain shuts off. so i think you can still keep with your tech mage idea (after all, General Corum basically looks like a high-tech mage), but you need to reinterpret the signifiers of the character in different ways.
if drawing a detail "feels right," or reminds you strongly of a design you've already seen, then you probably need to change it. genuinely new and different looking designs are little uncomfortable to draw, frankly, because you're breaking new ground. so don't be afraid to get beyond what seems comfortable while you're concepting--that's the territory where the greatest rewards still remain unmined, my friend. best of luck, and keep us posted with your progress!