feather fists. a long list of fighters with feather fists, if not, with less than stellar punching power, have been succesful in the boxing world: -chris byrd -hector camacho jr. -sven ottke -willie pep -joe calslappy -anselmo moreno -paulie malignaggi and many more...............
I chose poor stamina because it's the easiest thing to improve upon. Just gotta go harder on the roadwork, calisthenics and sparring. If you are talking about a trait that cannot be improved then I'd go with being feather fisted.