Random exotic idea #N: have genders depend on rank, but not in a predictable-for-foreigners way. E.g. military ranks change gender, in ascending order, by this list:
- animate masculine,
- animate feminine,
- inanimate feminine,
- animate neuter,
- inanimate masculine,
- inanimate neuter.
Because rocks are considered a symbol of power, and high ranks are considered *metaphorically* static like rocks and mountains.