preferably realistic answers. There are some obvious ones to change size of some of body parts, lets say making ankles more useful, or maybe something like 2 segmented arm (2 scratch your back better), or maybe a spine with fewer fatal spots than we have right now (too damn high)
so are we worried that it is a critical nerve which is also very vulnerable? if so, are not there many other (maybe more critical) things. Not saying we should not worry about it, but this seems a bit too specific.