I think losing a leg would be inconvenient to say the least. A foot would be half way there of course. I think to be bipedal is fairly basic to getting around.
I was once in a very strange movie where I did have to lose my right hand, and being right handed, that was really awkward. I was haranguing them for not making me lose my left hand!
Apparently losing a body part is pretty traumatic for anybody, whether it's a little finger nicked off by your local Yakuza [tattooed Japanese gangsters who sometimes cut off one of their own fingers as a test of loyalty] or whatever.
I keep my hands to myself because I don't want to lose body parts. Sometimes when I've been scuba diving I say [to other divers], 'No no, don't point like that,' because this big grouper is going to come and go 'gulp'. And so I'm pretty careful.
I would think you need to be mobile, so I want to keep my feet until last, and therefore the legs that attach them to the rest. Basically I'm a coward. I don't want to lose anything.