Gen is a brilliant example, yes. He goes through the very understandable process of mourning (or "whining" as Moira would have it) over the loss of his hand -- made all the more understandable by the fact that he's a Thief and his hands are the vital tools of his life's chosen trade. But while everybody thinks he's just moping and waiting to die, he's actually trying to re-train himself and make himself useful in a new capacity -- and then he comes back more awesome and brilliant than ever. Still having to work around his disability, still limited and frustrated by it in some respects, but at the same time capable of accomplishing more with one hand than most people could manage with two.

Which could have been dodgy if handled differently, because it might seem to imply that people with disabilities have no excuse for not being as awesome as Gen is, and if they aren't, it's because they haven't worked hard enough to overcome their physical limitations. But I don't think that the books really give that message at all. Gen is so much larger than life anyway that his physical disability serves to keep him human, and give the reader a chance to identify with his frustrations and struggles.