well, as far as I understand, some people behind Hive used a great metaphor for the platform - beehive.
So, in this context it makes sense to name the Hivepower ranks based on the social structure of it (3 types of honey bees in the hive):
(something like)
a) workers/worker bees (<5000 HIVE);
b) drones (>=5000 HIVE && < 500k HIVE)
c) queens/kings (>=500k HIVE)
https://en.wikipedia.org/wiki/Honey_bee_life_cycle
However, to be fair, personally I believe that division/ranks based on different Hivepower doesn't bring much benefits (it (division) may, say, in the army, though).
"Divide and conquer" / "divide and rule" (this is probably the reason why there're so-called women problems, negro problems, while they are just human problems)... Why divide at all?
What about not dividing but just being a Hiver/Hivian, no matter what his/her Hivepower is?