Depends on what your fighting style is. Years b4 when I practiced karate I would just used my legs if my arms were shorter. When I moved to jiu jitsu the arms became less of a burden since on the ground it wont count as much. When I moved to the current style (by which I belive I found what I was looking for) I found that the length of my arms did not realy influence if I was getting hit or not. At close quarters (and by that I mean only inches away from the opponent instead of 4-5 feet) the length of the arms don't realy matter since you're using your elbows, knees, fingers and palms. You can hit him with short arms as much as he can hit you with his long ones, arm length won't be a factor.
So just depends on the way you prefer to fight.