So some notes on the current simplification I am working through and current plans regarding the fluff/politics:
Planets are divided into a discrete number of indivisible 'Provinces', which form fiefs. A character can only rule one province directly at full efficiency. Each province is basically a mega city and its hinterland, in the far Space Future people live in megalopoli which does not seem too far fetched. An individual planet might have anywhere from one to a dozen of these depending upon how populated and rich it is. Non-Mars, or some stupidly rich/indulgent Noble's Safari Planet might have one, a bustling core world with billions of people far more.
Orbital fiefs will be similarly organised, 'L5 point colonies' might be one, 'Moon Cities' another, etc.
Directly holding more than one discrete fief is not really a thing, you can have vassals if you get your hands on multiple but any arrangements there are individual, if you give somebody the Moon Cities of Epsilon Kappa Four in return for half of their income and their fleets in time of war then go ahead!
Capital ships remain individually tracked, escort vessels not so much. Exponential sizes will exist for ground troops to cut down on having tons of little individual units.
@lordbelh I really like that idea! So – Space Nobles are genetically engineered 'Super People', they almost all tend to be gorgeous, skilled, fast, healthy, etc. The big thing though is that they are compatible with a suite of Hypertech cybernetic implants which lead to them having near perfect skill retention, inhumanly fast reflexes, slowed down subjective perception of time in crisis situations etc. They sell themselves as also having unmatched mental fortitude, mortality, etc and being the saviours of humanity come to drive back the (Space Elf) AI menace but a lot of that is propaganda.
The thing is that while said Hypertech cybernetic implants are very expensive they also allow one well trained person to double the effectiveness of a starship they command, or (with Hypertech powered armour and personal shield), kill three hundred professional soldiers using a Space Sword. Thus when the one in ten million non Space Noble is found who is compatible? If they are also competent and capable and healthy? They are snapped up by Space Nobles eager to bolster the ranks against their eternal Space Elf foe and granted sort of quasi-noble status. They are viewed as jumped up and inherently inferior though however capable they are, lacking the righteous certitude of a true Space Noble and no doubt of low character. Most of them probably then live up to being not up to par with Space Nobles given that they lack the genetic enhancement and best possible education/training from birth but PCs can be the exceptions.
Now politics and setting thoughts:
The Space Elves are AIs who seized control over the old Human Sphere several centuries ago, modelled upon human intelligence, they proceeded to split up into dozens or hundreds of factions, near elusively inhabit super sexy Space Elf bodies which are mostly biological, and are incredibly superior and smarmy whilst living 'lives' of ultra indulgent excess. They literally lord over the bulk of humanity and keep them as literal slaves, their armies formed of Star Janissaries indoctrinated since birth.
Space Nobles are significantly outnumbered by the Space Elves but are individually more than match for them (not just militarily) and their transcendent technology is a product of the Amalgamate Imperium. Whilst Space Nobles abhor 'True AI' as leading to the enslavement of humanity they are ruled by a vast (and distant) intelligence, a composite mind of the honoured dead uploaded on their distant throne world. The highest Space Noble honour is to be chosen to join the Amalgamate upon one's death and given Imperial policy is decided by the combined intelligence noble families desperately compete to win glory and renown for as many of their members as possible in the hope of swaying future policy.
The setting of the game is isolated from the main body of Imperial space, it will be decades before a wormhole can be established to provide immediate reinforcement and communication. Limited communication is possible but they are largely isolated, albeit in a rich and vital region of space which they are aggressively expanding into. The local Space Elves are fractured, their Princess having fallen in fighting the initial invasion. Shocked by the Space Noble ability to best them, they are fascinated, scared, also forced by necessity to treat Space Nobles as peers.
Lacking significant reinforcements, the Space Nobles are also in a position where they need to in some cases treat with the Space Elves, though they cannot necessarily do so entirely openly.
Space Nobles are all at least nominally on the same side but inter house (and intra house) rivalry is intense, this particular thrust of expansion being dominated by three major and rather more minor Houses. Since the Amalgamate Imperium is not stupid, the local Imperial Navy presence is dominated by one of those Minor Houses, but with contact having been largely cut off, that leaves the Imperial fleets floundering with lack of support and resupply.
Some worlds were conquered several years ago in the initial arrival and are well back from the front line, others are still contested or in bitterly disputed border regions. Those in the latter are very keen for everyone to continue to expand and push with full force, those holding fiefs in the former are much more keen on playing games of prestige and politics to establish who gets to rule the sector once contact is re-established. Why push so hard when losses are hard to replenish and reinforcements are only twenty years away? (Also much easier to big a big power player and extort concessions when maintaining a personal Fleet in Being).
