Just because you eventually come back does not mean you ignore all pain and can effectively function without an arm.
Maybe not the first few times, as shock sets in, but after you figure out that death isn't fatal, maybe you can learn to ignore the pain?
When I broke my leg a few months ago (critically failed a 'walk on icy ground' check
) I lay just like I landed screaming like a girl (literaly; my voice went up like 2 octaves) not dareing to move for fear of doing myself futher damage. If I
knew I'd have a fresh working body in a few minutes I may have been more inclined to push through the pain and get to the pizza place I was headed to and ask for a blanket and ambulance. I deffo
could have crawled there, or even possibly hopped if it weren't icy, but the pain and sensible notion of not aggravating the damage held me back.
I'm not saying that losing a limb won't slow you down a lot and make you nearly useless in combat, but I am saying that losing a limb should not insta-gib your character. Crawling around on one leg for a bit before bleeding out would be fun/funny to play (at least to me). Perhaps it would give me a chance to lob a bottle of greek fire at someone, or fire an already cocked and loaded crossbow. Heck if my dude is a force mage, perhaps I could pull a Ransōtengai
(http://bleach.wikia.com/wiki/Rans%C5%8Dtengai) and use telekinisis to control/replace my dude's smashed up limbs.