Authoritarian vs Egalitarian isn't that hard to think of. In Egalitarian hive minds there could be a lack of physical diversity between the different individuals (like naked mole rats) and/or multiple hives within a given empire. In Authoritarian there would be actual physical differences between castes like honey bees having queens, drones, and workers. Think interstellar eusociality rather than mono-mindedness.
sure, but what happens with the ethic bonuses?
they'd have to a little bit of extra coding and not just slap the ethics on to make it work. (like making ethics conditional)
imo, authoritarian should make your leader cap higher or something while egalitarian makes your worker drones slightly more productive.
spiritualism versus materialism makes sense, i don't get people's idea on how it doesn't work. a hive mind is still a mind that can hold beliefs, such as materialism or spirituality, spirituality don't necessitate god worship, merely non-materialistic beliefs, such as karma or feng shui, etc. a spiritualist ME, would likely just have everything about it the same, but it believes it is a separate entity from all of it's robots and the CPU it's running on, etc.
Militartist versus pacifist is pretty easy to follow, it's how the hive reacts to war.
xenophobia versus xenophilia is also pretty easy to grasp.
I think is they did do this rework, they should give hives a single "faction", and hive pops all are part of this faction with happiness. you can ignore factions by simply not picking an ethic other than GC. the faction represents the hives personal happiness with what it's doing. to balance this, the factions for hives would probably be different than normal ones, being slightly more restrictive, so you'll have to take a happiness hit if you need something done, but it'll still allow you.
in fact maybe not make it a faction, but a system that gives your empire stability modifiers for completing certain tasks or upholding your beliefs. you don't get happiness for like, just being friendly with people, but getting a new NAP, or winning a war, will give you temporary bonuses. a PAcifist will get upset when war happens, but especially it if has to declare war, etc. a spiritualist, will become upset when it colonizes gaia worlds but happy when it wins a war versus a ME or synth empire. etc.