My grandfather lost his legs at seperate instances, so his qait seemed fine to me (at this point Hershel would still be feeling like the leg is there and theres lots of muscle cramping from the brain trying to "find" the missing muscles), and you're trying to compensate for the uneven weight distribution - but then again I was more focused on actually looking at the leg itself, the way the pants hung empty and such, trying to find a misplaced fold or shadow.
I've been very impressed with the quality of effects (both practical and CG) on this show. I recently saw a behind the scenes segment where they showed how the like to go back and add CGI walkers to shots - you wouldn't have any idea they were CG unless you were actively looking for it.