..superorganism: a discrete "unit" of eusocial creatures.
that's a good term. In other words, all members of a single superorganism would together consider themselves to be a single "person".
Mechanically this would work out identically to other gameplay and thusly be purely cosmetic. optionally, we could include a special tech available to hive-species (based on FTL communication of some sort) which allows for planetary- and perhaps eventually civilization- unity.
Opinions differ, but i think it unlikely that we will have special, species-specific techs.
However, i do think it would be interesting include an advanced tech which functions as species-wide or empire-wide absolute unity.
A simple work-around for accomplishing these is: we already, I assume, plan to average out the total 'happiness' (whatever) score for a given planet to determine its productivity or likelihood of rebellion.
Here's an explanation
i put together of how it could work.
Moral and rebellions are the one part of hive-mind/collective/whatever creatures that i don't think i've wrapped my mind around, so i'd be especially interested in descriptions of how this might work.
I think you'll need multiple methods depending on how the hive works, a species with lots of individual superoganisms one colony* will work differently to a species with one superoganism per colonoy, or species with just one individual.
*They could gain unrest like any other race.
I don't see the need for any special rules as long as the superorganism is no larger than a planet. Riots, and rebellions make just as much sense if they are one (really big) individual fed up with the ruling empire or a billion individuals who feel the same way.
Even riots aren't too hard to make sense of in a multi-planetary superorganism (or group mind, collective consciousness, whatever)
. I would explain them as something like a temper tantrum. The trick is to figure out where they should be located. With riots it would be simplest and make sense if all planets rioted when the superorganism's happiness dropped below the threshold. This would be the consequence of being generally resistant to riots. When they hit, they are terrible. But that doesn't work with rebellions.
But if we have something like George (multi-planetary superorganism version)
-- and George is the only species in the empire-- the separation between planets/citizens and the ruling empire no longer makes as much sense. In George's mind there is no difference between the government and the governed. It's just all him. Kricktone's suggestion of understanding "allegiance" as "mental health" in George's instance, and thus rebellions and a psychological breakdown fits the mechanics well.
But again, which planets rebel? Making all planets rebel would essentially be "game-over".
"Unity" as i describe it here
in it's high levels isn't necessarily the property of some sort of superorganism. It could also belong to an extremely altruistic species.
I don't think there are any planned mechanism that would make talking about unity (or the lack thereof) on a sub-planetary level meaningful as anything but flavor text... but possibly something under "Government" will change that.